Commit Graph

219 Commits

Author SHA1 Message Date
DeHackEd 1f02ecc5a5 Make zfs_special_class_metadata_reserve_pct into a parameter
Exported and documented a new module parameter.

Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: DHE <git@dehacked.net>
Closes #8706
2019-05-07 15:34:42 -07:00
Brian Behlendorf caf9dd209f
Fix send/recv lost spill block
When receiving a DRR_OBJECT record the receive_object() function
needs to determine how to handle a spill block associated with the
object.  It may need to be removed or kept depending on how the
object was modified at the source.

This determination is currently accomplished using a heuristic which
takes in to account the DRR_OBJECT record and the existing object
properties.  This is a problem because there isn't quite enough
information available to do the right thing under all circumstances.
For example, when only the block size changes the spill block is
removed when it should be kept.

What's needed to resolve this is an additional flag in the DRR_OBJECT
which indicates if the object being received references a spill block.
The DRR_OBJECT_SPILL flag was added for this purpose.  When set then
the object references a spill block and it must be kept.  Either
it is update to date, or it will be replaced by a subsequent DRR_SPILL
record.  Conversely, if the object being received doesn't reference
a spill block then any existing spill block should always be removed.

Since previous versions of ZFS do not understand this new flag
additional DRR_SPILL records will be inserted in to the stream.
This has the advantage of being fully backward compatible.  Existing
ZFS systems receiving this stream will recreate the spill block if
it was incorrectly removed.  Updated ZFS versions will correctly
ignore the additional spill blocks which can be identified by
checking for the DRR_SPILL_UNMODIFIED flag.

The small downside to this approach is that is may increase the size
of the stream and of the received snapshot on previous versions of
ZFS.  Additionally, when receiving streams generated by previous
unpatched versions of ZFS spill blocks may still be lost.

OpenZFS-issue: https://www.illumos.org/issues/9952
FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233277

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8668
2019-05-07 15:18:44 -07:00
Richard Laager 0531c83c18 Eliminate useless double-bolding in man pages
As far as I know and can tell from testing, \fB\fB...\fR\fR is exactly
equivalent to \fB...\fR.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:04:35 -07:00
Richard Laager a5a6d82dda Alphabetize zpool-features.5 by short name
The features are sorted in the en_US locale, not the C locale.
Specifically, that means that bookmark_v2 comes _after_ bookmarks.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:04:28 -07:00
Richard Laager 6f07780147 Standardize .RE placement in zpool-features.5
This command is being used to unindent, so it should be at the end of
each block.  This is consistent with the other man pages.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:04:20 -07:00
Richard Laager 1644708fdc Add missing formatting to sha512 in zpool-features.5
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:04:13 -07:00
Richard Laager e1822912a9 Correct GUID of large_blocks in zpool-features.5
It is org.open-zfs:large_blocks (plural).

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:04:06 -07:00
Tom Caputi d0c3aa9cdd Change wording in zfs-module-parameters.5
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:03:59 -07:00
Richard Laager 063edd7fd8 Document that hole_birth is effectively useless
The first sentence of this commit comes from the wiki, and was
originally written by:
Rich Ercolani <rincebrain@gmail.com>
with changes by:
Tom Caputi <tcaputi@datto.com>

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
Closes #8642
2019-04-24 17:03:27 -07:00
Richard Laager 6ce7b2d9ad Document send_holes_without_birth_time
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:03:21 -07:00
Richard Laager e1fbe77110 Correct bookmark_v2 dependencies
encryption depends on bookmark_v2.

bookmark_v2 depends on bookmarks.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:03:12 -07:00
Richard Laager 4d256e897a Fix formatting for multi_vdev_crash_dump in zpool-features.5
This needs to use tabs instead of spaces to display correctly (i.e. with
things lined up).

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8641
2019-04-24 17:02:45 -07:00
cfzhu 5090f72743 Code improvement and bug fixes for QAT support
1. Support QAT when ZFS is root file-system:
   When ZFS module is loaded before QAT started, the QAT can
   be started again in post-process, e.g.:
   echo 0 > /sys/module/zfs/parameters/zfs_qat_compress_disable
   echo 0 > /sys/module/zfs/parameters/zfs_qat_encrypt_disable
   echo 0 > /sys/module/zfs/parameters/zfs_qat_checksum_disable
2. Verify alder checksum of the de-compress result
3. Allocate Digest, IV and AAD buffer in physical contiguous
   memory by QAT_PHYS_CONTIG_ALLOC.
4. Update the documentation for zfs_qat_compress_disable,
   zfs_qat_checksum_disable, zfs_qat_encrypt_disable.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Weigang Li <weigang.li@intel.com>
Signed-off-by: Chengfeix Zhu <chengfeix.zhu@intel.com>
Closes #8323 
Closes #8610
2019-04-16 12:38:36 -07:00
Richard Laager 6c0f78f8a3 Clarify GRUB's lack of support for sha512, skein, edonr
zfs.8 correctly said that GRUB did not support them, but
zpool-features.5 said that "Booting off pools...is supported."  Now,
zpool-features.5 discusses GRUB specifically and indicates its lack of
support for these features.  Also, I have clarified the wording in both
places to indicate that the pool feature cannot be used.  It's not a
filesystem dataset thing, but pool-wide.

I described this as "cannot be used".  I think technically the feature
can be enabled, just not active.  However, the effect is essentially the
same: you cannot enable those checksum algorithms on any dataset in the
pool, so you might as well not enable the feature (which is just
pointing a loaded gun at your foot).  In the past, an argument could be
made that having all the features enabled was useful for simplicity, as
long as you didn't activate the GRUB-incompatible features, but that's
getting less and less realistic over time.  A user can still do that,
but we should not encourage that.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
Closes #8446
2019-04-16 10:02:46 -07:00
Richard Laager 7886aa8a79 Reword the dedup limitation for Edon-R
The old wording was effectively "You can not use this (except you can)",
which just seems confusing.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
2019-04-16 10:02:07 -07:00
Richard Laager 393363c5ec Consistently captialize GUID for features
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
2019-04-16 10:01:51 -07:00
Richard Laager 612c4930dd Fix the spelling of deferred
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
2019-04-16 10:01:45 -07:00
Richard Laager 9042ca0e94 Refer to commands consistently in zpool-features.5
This had a mix of command vs subcommand, quoted vs not quoted, and
bolded vs. not bolded command names.

Also, fix man page sections from 1M (Solaris) to 8 (Linux).

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #8626
2019-04-16 10:01:31 -07:00
Brian Behlendorf 1b939560be
Add TRIM support
UNMAP/TRIM support is a frequently-requested feature to help
prevent performance from degrading on SSDs and on various other
SAN-like storage back-ends.  By issuing UNMAP/TRIM commands for
sectors which are no longer allocated the underlying device can
often more efficiently manage itself.

This TRIM implementation is modeled on the `zpool initialize`
feature which writes a pattern to all unallocated space in the
pool.  The new `zpool trim` command uses the same vdev_xlate()
code to calculate what sectors are unallocated, the same per-
vdev TRIM thread model and locking, and the same basic CLI for
a consistent user experience.  The core difference is that
instead of writing a pattern it will issue UNMAP/TRIM commands
for those extents.

The zio pipeline was updated to accommodate this by adding a new
ZIO_TYPE_TRIM type and associated spa taskq.  This new type makes
is straight forward to add the platform specific TRIM/UNMAP calls
to vdev_disk.c and vdev_file.c.  These new ZIO_TYPE_TRIM zios are
handled largely the same way as ZIO_TYPE_READs or ZIO_TYPE_WRITEs.
This makes it possible to largely avoid changing the pipieline,
one exception is that TRIM zio's may exceed the 16M block size
limit since they contain no data.

In addition to the manual `zpool trim` command, a background
automatic TRIM was added and is controlled by the 'autotrim'
property.  It relies on the exact same infrastructure as the
manual TRIM.  However, instead of relying on the extents in a
metaslab's ms_allocatable range tree, a ms_trim tree is kept
per metaslab.  When 'autotrim=on', ranges added back to the
ms_allocatable tree are also added to the ms_free tree.  The
ms_free tree is then periodically consumed by an autotrim
thread which systematically walks a top level vdev's metaslabs.

Since the automatic TRIM will skip ranges it considers too small
there is value in occasionally running a full `zpool trim`.  This
may occur when the freed blocks are small and not enough time
was allowed to aggregate them.  An automatic TRIM and a manual
`zpool trim` may be run concurrently, in which case the automatic
TRIM will yield to the manual TRIM.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Contributions-by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Contributions-by: Tim Chase <tim@chase2k.com>
Contributions-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8419 
Closes #598
2019-03-29 09:13:20 -07:00
Olaf Faaland 060f0226e6 MMP interval and fail_intervals in uberblock
When Multihost is enabled, and a pool is imported, uberblock writes
include ub_mmp_delay to allow an importing node to calculate the
duration of an activity test.  This value, is not enough information.

If zfs_multihost_fail_intervals > 0 on the node with the pool imported,
the safe minimum duration of the activity test is well defined, but does
not depend on ub_mmp_delay:

zfs_multihost_fail_intervals * zfs_multihost_interval

and if zfs_multihost_fail_intervals == 0 on that node, there is no such
well defined safe duration, but the importing host cannot tell whether
mmp_delay is high due to I/O delays, or due to a very large
zfs_multihost_interval setting on the host which last imported the pool.
As a result, it may use a far longer period for the activity test than
is necessary.

This patch renames ub_mmp_sequence to ub_mmp_config and uses it to
record the zfs_multihost_interval and zfs_multihost_fail_intervals
values, as well as the mmp sequence.  This allows a shorter activity
test duration to be calculated by the importing host in most situations.
These values are also added to the multihost_history kstat records.

It calculates the activity test duration differently depending on
whether the new fields are present or not; for importing pools with
only ub_mmp_delay, it uses

(zfs_multihost_interval + ub_mmp_delay) * zfs_multihost_import_intervals

Which results in an activity test duration less sensitive to the leaf
count.

In addition, it makes a few other improvements:
* It updates the "sequence" part of ub_mmp_config when MMP writes
  in between syncs occur.  This allows an importing host to detect MMP
  on the remote host sooner, when the pool is idle, as it is not limited
  to the granularity of ub_timestamp (1 second).
* It issues writes immediately when zfs_multihost_interval is changed
  so remote hosts see the updated value as soon as possible.
* It fixes a bug where setting zfs_multihost_fail_intervals = 1 results
  in immediate pool suspension.
* Update tests to verify activity check duration is based on recorded
  tunable values, not tunable values on importing host.
* Update tests to verify the expected number of uberblocks have valid
  MMP fields - fail_intervals, mmp_interval, mmp_seq (sequence number),
  that sequence number is incrementing, and that uberblock values match
  tunable settings.

Reviewed-by: Andreas Dilger <andreas.dilger@whamcloud.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #7842
2019-03-21 12:47:57 -07:00
Alexander Motin 1af240f3b5 Add separate aggregation limit for non-rotating media
Before sequential scrub patches ZFS never aggregated I/Os above 128KB.
Sequential scrub bumped that to 1MB, supposedly to reduce number of
head seeks for spinning disks.  But for SSDs it makes little to no
sense, especially on FreeBSD, where due to MAXPHYS limitation device
will likely still see bunch of 128KB I/Os instead of one large.
Having more strict aggregation limit for SSDs allows to avoid
allocation of large memory buffer and copy to/from it, that is a
serious problem when throughput reaches gigabytes per second.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Closes #8494
2019-03-13 12:00:10 -07:00
Tom Caputi 579ce7c5ae Add bookmark v2 on-disk feature
This patch adds the bookmark v2 feature to the on-disk format. This
feature will be needed for the upcoming redacted sends and for an
upcoming fix that for raw receives. The feature is not currently
used by any code and thus this change is a no-op, aside from the
fact that the user can now enable the feature.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Issue #8308
2019-03-13 10:58:39 -07:00
Olaf Faaland db2af93d72 Increase default zfs_multihost_fail_intervals and import_intervals
By default, when multihost is enabled for a pool, the pool is
suspended if (zfs_multihost_fail_intervals*zfs_multihost_interval) ms
pass without a successful MMP write.  This is the recommended
configuration.

The default value for zfs_multihost_fail_intervals has been 5, and the
default value for zfs_multihost_interval has been 1000, so pool
suspension occurred at 5 seconds.

There have been multiple cases where a single misbehaving device in a
pool triggered a SCSI reset, and all I/O paused for 5-6 seconds.  This
in turn caused MMP to suspend the pool.

In the cases observed, the rest of the devices were healthy and the
pool was otherwise correctly performing I/O.  The reset was handled
correctly by ZFS, and by suspending the pool MMP made replacing the
device more difficult as well as forcing the host to be rebooted.

Increase the default value of zfs_multihost_fail_intervals to 10, so
that MMP tolerates up to 10 seconds of failed MMP writes before
suspending the pool.

Increase the default value of zfs_multihost_import_intervals to 20, to
maintain the 2:1 safety factor.  This results in a force import taking
approximately 20 seconds when MMP is enabled, with default values.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@whamcloud.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #7709 
Closes #8495
2019-03-13 09:50:48 -07:00
Matthew Ahrens 87c25d567f abd_alloc should use scatter for >1K allocations
abd_alloc() normally does scatter allocations, thus solving the problem
that ABD originally set out to: the bulk of ZFS's allocations are single
pages, which are faster to allocate and free, and don't suffer from
internal fragmentation (and the inability to reclaim memory because some
buffers in the slab are still allocated).

However, the current code does linear allocations for 4KB and smaller
allocations, defeating the purpose of ABD.

Scatter ABD's use at least one page each, so sub-page allocations waste
some space when allocated as scatter (e.g. 2KB scatter allocation wastes
half of each page).  Using linear ABD's for small allocations means that
they will be put on slabs which contain many allocations.  This can
improve memory efficiency, but it also makes it much harder for ARC
evictions to actually free pages, because all the buffers on one slab
need to be freed in order for the slab (and underlying pages) to be
freed.  Typically, 512B and 1KB kmem caches have 16 buffers per slab, so
it's possible for them to actually waste more memory than scatter (one
page per buf = wasting 3/4 or 7/8th; one buf per slab = wasting
15/16th).

Spill blocks are typically 512B and are heavily used on systems running
selinux with the default dnode size and the `xattr=sa` property set.

By default we will use linear allocations for 512B and 1KB, and scatter
allocations for larger (1.5KB and up).

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by:  DHE <git@dehacked.net>
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #8455
2019-02-28 17:52:55 -08:00
Tim Chase 638dd5f44e zio_deadman_impl() fix and enhancement
Add the zio_deadman_log_all tunable to print all zios in
zio_deadman_impl().  Also, in all cases, display the depth of the
zio relative to the original parent zio.  This is meant to be used by
developers to gain diagnostic information for hangs which don't involve
fully set-up zio trees or are otherwise stuck or hung in an early stage.

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #8362
2019-02-15 12:44:24 -08:00
Alek P 65282ee9e0 Freeing throttle should account for holes
Deletion throttle currently does not account for holes in a file.
This means that it can activate when it shouldn't.
To fix it we switch the throttle to be based on the number of
L1 blocks we will have to dirty when freeing

Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #7725 
Closes #7888
2019-02-12 12:01:08 -08:00
Alek P dcec0a12c8 port async unlinked drain from illumos-nexenta
This patch is an async implementation of the existing sync
zfs_unlinked_drain() function. This function is called at mount time and
is responsible for freeing znodes that we didn't get to freeing before.
We don't have to hold mounting of the dataset until the unlinked list is
fully drained as is done now. Since we can process the unlinked set
asynchronously this results in a better user experience when mounting a
dataset with entries in the unlinked set.

Reviewed by: Jorgen Lundman <lundman@lundman.net>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #8142
2019-02-12 10:41:15 -08:00
Serapheim Dimitropoulos c853f382db Change target size of metaslabs from 256GB to 16GB
= Old behavior

For vdev sizes 100GB to 50TB we keep ~200 metaslabs per
vdev and the metaslab size grows from 512MB to 256GB.
For vdev's bigger than that we start increasing the
number of metaslabs until we hit the 128K limit.

= New Behavior

For vdev sizes 100GB to 3TB we keep ~200 metaslabs per
vdev and the metaslab size grows from 512MB to 16GB.
For vdev's bigger than that we start increasing the
number of metaslabs until we hit the 128K limit.

= Reasoning

The old behavior makes metaslabs grow in size when
the vdev range is between 3TB (ms_size 16GB) and
32PB (ms_size 256GB). Even though keeping the number
of metaslabs is good in terms of potential number of
I/Os per TXG, these bigger metaslabs take longer
to be loaded and after they are loaded they can
take up a lot of memory because of their range trees.

This change tries to put a boundary in memory and
loading time for the specific range of vdev sizes.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8324
2019-01-25 16:38:27 -08:00
Brian Behlendorf 64bdf63f5c
ztest: split block reconstruction
Increase the default allowed number of reconstruction attempts.
There's not an exact right number for this setting.  It needs
to be set large enough to cover any realistic failure scenarios
and small enough to avoid stalling the IO pipeline and invoking
the dead man detection.

The current value of 256 was empirically determined to be too
low based on multi-day runs of ztest.  The fault injection code
would inject more damage than could be reconstructed given the
relatively small number of attempts.  However, in all observed
cases the block could be reconstructed using a slightly higher
limit.

Based on local testing increasing the default value to 4096 was
determined to strike the best balance.  Checking all combinations
takes less than 10s in the worst case, and has so far eliminated
the vast majority of false positives detected by ztest.  This
delay is roughly on par with how long retries may be performed
to a misbehaving HDD and was deemed to be reasonable.  Better to
err on the side of a brief delay rather than fail to reconstruct
the data.

Lastly, the -Y flag has been added to zdb to make it easy to try all
possible combinations when performing split block reconstruction.
For badly damaged blocks with 18 splits, they can be fully enumerated
within a few minutes.  This has been done to ensure permanent errors
are never incorrectly reported when ztest verifies the pool with zdb.

Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8271
2019-01-16 14:10:02 -08:00
Brian Behlendorf 6e91a72fe3
Disable 'zfs remap' command
The implementation of 'zfs remap' has proven to be problematic since
it modifies the objset (but not its logical contents) by dirtying
metadata without owning it.  The consequence of which is that
dmu_objset_remap_indirects() is vulnerable to certain races.

For example, if we are in the middle of receiving into the filesystem
while it is being remapped.  Then it is possible we could evict the
objset when the receive completes (see dsl_dataset_clone_swap_sync_impl,
or dmu_recv_end_sync), but dmu_objset_remap_indirects() may be still
using the objset.  The result of which would be a panic.

Extended runs of ztest(8) have exposed other possible races which
can occur when using 'zfs remap'.  Several of these have been fixed
but there may be others which have not yet been encountered and
diagnosed.

Furthermore, the ability to manually remap a filesystem is no longer
particularly useful now that the removal code can map large chunks.
Coupled with the fact that explaining what this command does and why
it may be useful requires a detailed understanding of the internals
of device removal.  These are details users should not be bothered
with.

Therefore, the 'zfs remap' command is being disabled but not entirely
removed.  It may be removed in the future or potentially reworked
to address the issues described above.  Since 'zfs remap' has never
been part of a tagged release its removal is expected to have
minimal impact.

The ZTS tests have been updated to continue to exercise the command
to prevent atrophy, but it has been removed entirely from ztest(8).

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8238
2019-01-15 15:46:58 -08:00
George Wilson 619f097693 OpenZFS 9102 - zfs should be able to initialize storage devices
PROBLEM
========

The first access to a block incurs a performance penalty on some platforms
(e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are
"thick provisioned", where supported by the platform (VMware). This can
create a large delay in getting a new virtual machines up and running (or
adding storage to an existing Engine). If the thick provision step is
omitted, write performance will be suboptimal until all blocks on the LUN
have been written.

SOLUTION
=========

This feature introduces a way to 'initialize' the disks at install or in the
background to make sure we don't incur this first read penalty.

When an entire LUN is added to ZFS, we make all space available immediately,
and allow ZFS to find unallocated space and zero it out. This works with
concurrent writes to arbitrary offsets, ensuring that we don't zero out
something that has been (or is in the middle of being) written. This scheme
can also be applied to existing pools (affecting only free regions on the
vdev). Detailed design:
        - new subcommand:zpool initialize [-cs] <pool> [<vdev> ...]
                - start, suspend, or cancel initialization
        - Creates new open-context thread for each vdev
        - Thread iterates through all metaslabs in this vdev
        - Each metaslab:
                - select a metaslab
                - load the metaslab
                - mark the metaslab as being zeroed
                - walk all free ranges within that metaslab and translate
                  them to ranges on the leaf vdev
                - issue a "zeroing" I/O on the leaf vdev that corresponds to
                  a free range on the metaslab we're working on
                - continue until all free ranges for this metaslab have been
                  "zeroed"
                - reset/unmark the metaslab being zeroed
                - if more metaslabs exist, then repeat above tasks.
                - if no more metaslabs, then we're done.

        - progress for the initialization is stored on-disk in the vdev’s
          leaf zap object. The following information is stored:
                - the last offset that has been initialized
                - the state of the initialization process (i.e. active,
                  suspended, or canceled)
                - the start time for the initialization

        - progress is reported via the zpool status command and shows
          information for each of the vdevs that are initializing

Porting notes:
- Added zfs_initialize_value module parameter to set the pattern
  written by "zpool initialize".
- Added zfs_vdev_{initializing,removal}_{min,max}_active module options.

Authored by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Wren Kennedy <john.kennedy@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: loli10K <ezomori.nozomu@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Signed-off-by: Tim Chase <tim@chase2k.com>
Ported-by: Tim Chase <tim@chase2k.com>

OpenZFS-issue: https://www.illumos.org/issues/9102
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210eb
Closes #8230
2019-01-07 10:37:26 -08:00
Tony Hutter c66401fae0 Add enclosure_symlinks option to vdev_id
Add an 'enclosure_symlinks' option to vdev_id.conf.  This creates
consistently named symlinks to the enclosure devices (/dev/sg*) based
off the configuration in vdev_id.conf.  The enclosure symlinks show
up in /dev/by-enclosure/<prefix>-<channel><num>.  The links make it
make it easy to run sg_ses on a particular enclosure device.  The
enclosure links are created in addition to the normal
/dev/disk/by-vdev links.

'enclosure_symlinks' is only valid in sas_direct configurations.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Simon Guest <simon.guest@tesujimath.org>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #8194
2018-12-14 17:27:49 -08:00
Prakash Surya 53b1f5eac6 OpenZFS 9963 - Separate tunable for disabling ZIL vdev flush
Porting Notes:
* Add options to zfs-module-parameters(5) man page.
* zfs_nocacheflush move to vdev.c instead of vdev_disk.c, since
  the latter doesn't get built for user space.

Authored by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: George Melikov <mail@gmelikov.ru>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/9963
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f8fdf68125
Closes #8186
2018-12-07 11:06:29 -08:00
Brian Behlendorf 7c9a42921e
Detect IO errors during device removal
* Detect IO errors during device removal

While device removal cannot verify the checksums of individual
blocks during device removal, it can reasonably detect hard IO
errors from the leaf vdevs.  Failure to perform this error
checking can result in device removal completing successfully,
but moving no data which will permanently corrupt the pool.

Situation 1: faulted/degraded vdevs

In the configuration shown below, the removal of mirror-0 will
permanently corrupt the pool.  Device removal will preferentially
copy data from 'vdev1 -> vdev3' and from 'vdev2 -> vdev4'.  Which
in this case will result in nothing being copied since one vdev
in each of those groups in unavailable.  However, device removal
will complete successfully since all IO errors are ignored.

  tank                DEGRADED     0     0     0
    mirror-0          DEGRADED     0     0     0
      /var/tmp/vdev1  FAULTED      0     0     0  external fault
      /var/tmp/vdev2  ONLINE       0     0     0
    mirror-1          DEGRADED     0     0     0
      /var/tmp/vdev3  ONLINE       0     0     0
      /var/tmp/vdev4  FAULTED      0     0     0  external fault

This issue is resolved by updating the source child selection
logic to exclude unreadable leaf vdevs.  Additionally, unwritable
destination child vdevs which can never succeed are skipped to
prevent generating a large number of write IO errors.

Situation 2: individual hard IO errors

During removal if an unexpected hard IO error is encountered when
either reading or writing the child vdev the entire removal
operation is cancelled.  While it may be possible to reconstruct
the data after removal that cannot be guaranteed.  The only
strictly safe thing to do is to cancel the removal.

As a future improvement we may want to instead suspend the removal
process and allow the damaged region to be retried.  But that work
is left for another time, hard IO errors during the removal process
are expected to be exceptionally rare.

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #6900
Closes #8161
2018-12-04 09:37:37 -08:00
Rich Ercolani 62ee31adce Fix typo in update to zfs-module-parameters(5)
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <guss80@gmail.com>
Reviewed-by: bunder2015 <omfgbunder@gmail.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes #8153
2018-11-26 10:23:58 -08:00
Tony Hutter ad796b8a3b Add zpool status -s (slow I/Os) and -p (parseable)
This patch adds a new slow I/Os (-s) column to zpool status to show the
number of VDEV slow I/Os. This is the number of I/Os that didn't
complete in zio_slow_io_ms milliseconds. It also adds a new parsable
(-p) flag to display exact values.

 	NAME         STATE     READ WRITE CKSUM  SLOW
 	testpool     ONLINE       0     0     0     -
	  mirror-0   ONLINE       0     0     0     -
 	    loop0    ONLINE       0     0     0    20
 	    loop1    ONLINE       0     0     0     0

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #7756
Closes #6885
2018-11-08 16:47:24 -08:00
Richard Elling 6644e5bb6e Update zfs-events.5 with info from PSARC 2009/497
Update zfs-events.5 with info from PSARC 2009/497 regarding ereport fields.
Also updates ZIO_STAGE_* and ZIO_FLAG_* descriptions to match current source.

Reviewed by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Elling <Richard.Elling@RichardElling.com>
Closes #8057
2018-11-01 15:54:55 -07:00
Tom Caputi 80a91e7469 Defer new resilvers until the current one ends
Currently, if a resilver is triggered for any reason while an
existing one is running, zfs will immediately restart the existing
resilver from the beginning to include the new drive. This causes
problems for system administrators when a drive fails while another
is already resilvering. In this case, the optimal thing to do to
reduce risk of data loss is to wait for the current resilver to end
before immediately replacing the second failed drive, which allows
the system to operate with two incomplete drives for the minimum
amount of time.

This patch introduces the resilver_defer feature that essentially
does this for the admin without forcing them to wait and monitor
the resilver manually. The change requires an on-disk feature
since we must mark drives that are part of a deferred resilver in
the vdev config to ensure that we do not assume they are done
resilvering when an existing resilver completes.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: @mmaybee 
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #7732
2018-10-18 21:06:18 -07:00
Matthew Ahrens dfbe267503 OpenZFS 9617 - too-frequent TXG sync causes excessive write inflation
Porting notes:
* Renamed zfs_dirty_data_sync_pct to zfs_dirty_data_sync_percent and
  changed the type to be consistent with the other dirty module params.
* Updated zfs-module-parameters.5 accordingly.

Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://illumos.org/issues/9617
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7928f4ba
Closes #7976
2018-10-04 13:13:28 -07:00
Brian Behlendorf 1258bd778e
Refine split block reconstruction
Due to a flaw in 4589f3ae the number of unique combinations
could be calculated incorrectly.  This could result in the
random combinations reconstruction being used when it would
have been possible to check all combinations.

This change fixes the unique combinations calculation and
simplifies the reconstruction logic by maintaining a per-
segment list of unique copies.

The vdev_indirect_splits_damage() function was introduced
to validate both the enumeration and random reconstruction
logic with ztest.  It is implemented such it will never
make a known recoverable block unrecoverable.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #6900 
Closes #7934
2018-10-01 10:36:34 -07:00
DeHackEd 81155b296d Fix allocation_classes GUID in zpool-features(5)
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: DHE <git@dehacked.net>
Closes #7920
2018-09-18 08:59:47 -07:00
Don Brady cc99f275a2 Pool allocation classes
Allocation Classes add the ability to have allocation classes in a
pool that are dedicated to serving specific block categories, such
as DDT data, metadata, and small file blocks. A pool can opt-in to
this feature by adding a 'special' or 'dedup' top-level VDEV.

Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Reviewed-by: Håkan Johansson <f96hajo@chalmers.se>
Reviewed-by: Andreas Dilger <andreas.dilger@chamcloud.com>
Reviewed-by: DHE <git@dehacked.net>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Gregor Kopka <gregor@kopka.net>
Reviewed-by: Kash Pande <kash@tripleback.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes #5182
2018-09-05 18:33:36 -07:00
Tom Caputi c3bd3fb4ac OpenZFS 9403 - assertion failed in arc_buf_destroy()
Assertion failed in arc_buf_destroy() when concurrently reading
block with checksum error.

Porting notes:
* The ability to zinject decompression errors has been added, but
  this only works at the zio_decompress() level, where we have all
  of the info we need to match against the user's zinject options.
* The decompress_fault test has been added to test the new zinject
  functionality
* We attempted to set zio_decompress_fail_fraction to (1 << 18) in
  ztest for further test coverage. Although this did uncover a few
  low priority issues, this unfortuantely also causes ztest to
  ASSERT in many locations where the code is working correctly since
  it is designed to fail on IO errors. Developers can manually set
  this variable with the '-o' option to find and debug issues.

Authored by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Matt Ahrens <mahrens@delphix.com>
Ported-by: Tom Caputi <tcaputi@datto.com>

OpenZFS-issue: https://illumos.org/issues/9403
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/fa98e487a9
Closes #7822
2018-08-29 11:33:33 -07:00
Toomas Soome 5fadb7fb0c OpenZFS 8906 - uts: illumos rootfs should support salted cksum
Porting notes:
* As of grub-2.02 these checksums are not supported.  However, as
  pointed out in #6501 there are alternatives such as EFISTUB which
  work and have no such restriction.  A warning was added to the
  checksum property section of the zfs.8 man page.

Authored by: Toomas Soome <tsoome@me.com>
Reviewed by: C Fraire <cfraire@me.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Yuri Pankov <yuripv@yuripv.net>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://illumos.org/issues/8906
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7dec52f
Closes #6501
Closes #7714
2018-07-27 08:35:28 -07:00
Matthew Ahrens 2e5dc449c1 OpenZFS 9337 - zfs get all is slow due to uncached metadata
This project's goal is to make read-heavy channel programs and zfs(1m)
administrative commands faster by caching all the metadata that they will
need in the dbuf layer. This will prevent the data from being evicted, so
that any future call to i.e. zfs get all won't have to go to disk (very
much). There are two parts:

The dbuf_metadata_cache. We identify what to put into the cache based on
the object type of each dbuf.  Caching objset properties os
{version,normalization,utf8only,casesensitivity} in the objset_t. The reason
these needed to be cached is that although they are queried frequently,
they aren't stored in a dbuf type which we can easily recognize and cache in
the dbuf layer; instead, we have to explicitly store them. There's already
existing infrastructure for maintaining cached properties in the objset
setup code, so I simply used that.

Performance Testing:

 - Disabled kmem_flags
 - Tuned dbuf_cache_max_bytes very low (128K)
 - Tuned zfs_arc_max very low (64M)

Created test pool with 400 filesystems, and 100 snapshots per filesystem.
Later on in testing, added 600 more filesystems (with no snapshots) to make
sure scaling didn't look different between snapshots and filesystems.

Results:

    | Test                   | Time (trunk / diff) | I/Os (trunk / diff) |
    +------------------------+---------------------+---------------------+
    | zpool import           |     0:05 / 0:06     |    12.9k / 12.9k    |
    | zfs get all (uncached) |     1:36 / 0:53     |    16.7k / 5.7k     |
    | zfs get all (cached)   |     1:36 / 0:51     |    16.0k / 6.0k     |

Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Thomas Caputi <tcaputi@datto.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Ported-by: Alek Pinchuk <apinchuk@datto.com>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>

OpenZFS-issue: https://illumos.org/issues/9337
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7dec52f
Closes #7668
2018-07-12 10:49:27 -07:00
Don Brady e4e94ca315 OpenZFS 9426 - metaslab size can exceed offset addressable by spacemap
Authored by: Don Brady <don.brady@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@joyent.com>

OpenZFS-issue: https://www.illumos.org/issues/9426
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f1c88afb1
Closes #7700
2018-07-11 15:55:48 -07:00
Serapheim Dimitropoulos a7ed98d8b5 OpenZFS 9330 - stack overflow when creating a deeply nested dataset
Datasets that are deeply nested (~100 levels) are impractical. We just
put a limit of 50 levels to newly created datasets. Existing datasets
should work without a problem.

The problem can be seen by attempting to create a dataset using the -p
option with many levels:

    panic[cpu0]/thread=ffffff01cd282c20: BAD TRAP: type=8 (#df Double fault) rp=ffffffff

    fffffffffbc3aa60 unix:die+100 ()
    fffffffffbc3ab70 unix:trap+157d ()
    ffffff00083d7020 unix:_patch_xrstorq_rbx+196 ()
    ffffff00083d7050 zfs:dbuf_rele+2e ()
    ...
    ffffff00083d7080 zfs:dsl_dir_close+32 ()
    ffffff00083d70b0 zfs:dsl_dir_evict+30 ()
    ffffff00083d70d0 zfs:dbuf_evict_user+4a ()
    ffffff00083d7100 zfs:dbuf_rele_and_unlock+87 ()
    ffffff00083d7130 zfs:dbuf_rele+2e ()
    ... The block above repeats once per directory in the ...
    ... create -p command, working towards the root ...
    ffffff00083db9f0 zfs:dsl_dataset_drop_ref+19 ()
    ffffff00083dba20 zfs:dsl_dataset_rele+42 ()
    ffffff00083dba70 zfs:dmu_objset_prefetch+e4 ()
    ffffff00083dbaa0 zfs:findfunc+23 ()
    ffffff00083dbb80 zfs:dmu_objset_find_spa+38c ()
    ffffff00083dbbc0 zfs:dmu_objset_find+40 ()
    ffffff00083dbc20 zfs:zfs_ioc_snapshot_list_next+4b ()
    ffffff00083dbcc0 zfs:zfsdev_ioctl+347 ()
    ffffff00083dbd00 genunix:cdev_ioctl+45 ()
    ffffff00083dbd40 specfs:spec_ioctl+5a ()
    ffffff00083dbdc0 genunix:fop_ioctl+7b ()
    ffffff00083dbec0 genunix:ioctl+18e ()
    ffffff00083dbf10 unix:brand_sys_sysenter+1c9 ()

Porting notes:
* Added zfs_max_dataset_nesting module option with documentation.
* Updated zfs_rename_014_neg.ksh for Linux.
* Increase the zfs.sh stack warning to 15K.  Enough time has passed
  that 16K can be reasonably assumed to be the default value.  It
  was increased in the 3.15 kernel released in June of 2014.

Authored by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>

OpenZFS-issue: https://www.illumos.org/issues/9330
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/757a75a
Closes #7681
2018-07-09 13:02:50 -07:00
Serapheim Dimitropoulos 4d044c4c1d OpenZFS 9238 - ZFS Spacemap Encoding V2
Motivation
==========

The current space map encoding has the following disadvantages:
[1] Assuming 512 sector size each entry can represent at most 16MB for a segment.
    This makes the encoding very inefficient for large regions of space.
[2] As vdev-wide space maps have started to be used by new features (i.e.
    device removal, zpool checkpoint) we've started imposing limits in the
    vdevs that can be used with them based on the maximum addressable offset
    (currently 64PB for a top-level vdev).

New encoding
============

The layout can be found at space_map.h and it remains backwards compatible with
the old one. The introduced two-word entry format, besides extending the limits
imposed by the single-entry layout, also includes a vdev field and some extra
padding after its prefix.

The extra padding after the prefix should is reserved for future usage (e.g.
new prefixes for future encodings or new fields for flags). The new vdev field
not only makes the space maps more self-descriptive, but also opens the doors
for pool-wide space maps (expected to be used in the log spacemap project).

One final important note is that the number of bits used for vdevs is reduced
to 24 bits for blkptrs. That was decided as we don't know of any setups that
use more than 16M vdevs for the time being and we wanted to fit the vdev field
in the space map. In addition that gives us some extra bits in dva_t.

Other references:
=================

The new encoding is also discussed towards the end of the Log Space Map
presentation from 2017's OpenZFS summit.
Link: https://www.youtube.com/watch?v=jj2IxRkl5bQ

Authored by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <gwilson@zfsmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Gordon Ross <gwr@nexenta.com>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>

OpenZFS-commit: https://github.com/openzfs/openzfs/commit/90a56e6d
OpenZFS-issue: https://www.illumos.org/issues/9238
Closes #7665
2018-07-05 12:02:34 -07:00
Tim Chase 3be1eb29da Fix formatting in zpool-features(5)
The formatting of the features beginning with large_blocks was broken
when the zpool_checkpoint feature was added.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7658
2018-06-27 09:34:25 -07:00
Serapheim Dimitropoulos d2734cce68 OpenZFS 9166 - zfs storage pool checkpoint
Details about the motivation of this feature and its usage can
be found in this blogpost:

    https://sdimitro.github.io/post/zpool-checkpoint/

A lightning talk of this feature can be found here:
https://www.youtube.com/watch?v=fPQA8K40jAM

Implementation details can be found in big block comment of
spa_checkpoint.c

Side-changes that are relevant to this commit but not explained
elsewhere:

* renames members of "struct metaslab trees to be shorter without
  losing meaning

* space_map_{alloc,truncate}() accept a block size as a
  parameter. The reason is that in the current state all space
  maps that we allocate through the DMU use a global tunable
  (space_map_blksz) which defauls to 4KB. This is ok for metaslab
  space maps in terms of bandwirdth since they are scattered all
  over the disk. But for other space maps this default is probably
  not what we want. Examples are device removal's vdev_obsolete_sm
  or vdev_chedkpoint_sm from this review. Both of these have a
  1:1 relationship with each vdev and could benefit from a bigger
  block size.

Porting notes:

* The part of dsl_scan_sync() which handles async destroys has
  been moved into the new dsl_process_async_destroys() function.

* Remove "VERIFY(!(flags & FWRITE))" in "kernel.c" so zhack can write
  to block device backed pools.

* ZTS:
  * Fix get_txg() in zpool_sync_001_pos due to "checkpoint_txg".

  * Don't use large dd block sizes on /dev/urandom under Linux in
    checkpoint_capacity.

  * Adopt Delphix-OS's setting of 4 (spa_asize_inflation =
    SPA_DVAS_PER_BP + 1) for the checkpoint_capacity test to speed
    its attempts to fill the pool

  * Create the base and nested pools with sync=disabled to speed up
    the "setup" phase.

  * Clear labels in test pool between checkpoint tests to avoid
    duplicate pool issues.

  * The import_rewind_device_replaced test has been marked as "known
    to fail" for the reasons listed in its DISCLAIMER.

  * New module parameters:

      zfs_spa_discard_memory_limit,
      zfs_remove_max_bytes_pause (not documented - debugging only)
      vdev_max_ms_count (formerly metaslabs_per_vdev)
      vdev_min_ms_count

Authored by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>

OpenZFS-issue: https://illumos.org/issues/9166
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7159fdb8
Closes #7570
2018-06-26 10:07:42 -07:00