Various module parameters such as `zfs_arc_max` were originally
`uint64_t` on OpenSolaris/Illumos, but were changed to `unsigned long`
for Linux compatibility because Linux's kernel default module parameter
implementation did not support 64-bit types on 32-bit platforms. This
caused problems when porting OpenZFS to Windows because its LLP64 memory
model made `unsigned long` a 32-bit type on 64-bit, which created the
undesireable situation that parameters that should accept 64-bit values
could not on 64-bit Windows.
Upon inspection, it turns out that the Linux kernel module parameter
interface is extensible, such that we are allowed to define our own
types. Rather than maintaining the original type change via hacks to to
continue shrinking module parameters on 32-bit Linux, we implement
support for 64-bit module parameters on Linux.
After doing a review of all 64-bit kernel parameters (found via the man
page and also proposed changes by Andrew Innes), the kernel module
parameters fell into a few groups:
Parameters that were originally 64-bit on Illumos:
* dbuf_cache_max_bytes
* dbuf_metadata_cache_max_bytes
* l2arc_feed_min_ms
* l2arc_feed_secs
* l2arc_headroom
* l2arc_headroom_boost
* l2arc_write_boost
* l2arc_write_max
* metaslab_aliquot
* metaslab_force_ganging
* zfetch_array_rd_sz
* zfs_arc_max
* zfs_arc_meta_limit
* zfs_arc_meta_min
* zfs_arc_min
* zfs_async_block_max_blocks
* zfs_condense_max_obsolete_bytes
* zfs_condense_min_mapping_bytes
* zfs_deadman_checktime_ms
* zfs_deadman_synctime_ms
* zfs_initialize_chunk_size
* zfs_initialize_value
* zfs_lua_max_instrlimit
* zfs_lua_max_memlimit
* zil_slog_bulk
Parameters that were originally 32-bit on Illumos:
* zfs_per_txg_dirty_frees_percent
Parameters that were originally `ssize_t` on Illumos:
* zfs_immediate_write_sz
Note that `ssize_t` is `int32_t` on 32-bit and `int64_t` on 64-bit. It
has been upgraded to 64-bit.
Parameters that were `long`/`unsigned long` because of Linux/FreeBSD
influence:
* l2arc_rebuild_blocks_min_l2size
* zfs_key_max_salt_uses
* zfs_max_log_walking
* zfs_max_logsm_summary_length
* zfs_metaslab_max_size_cache_sec
* zfs_min_metaslabs_to_flush
* zfs_multihost_interval
* zfs_unflushed_log_block_max
* zfs_unflushed_log_block_min
* zfs_unflushed_log_block_pct
* zfs_unflushed_max_mem_amt
* zfs_unflushed_max_mem_ppm
New parameters that do not exist in Illumos:
* l2arc_trim_ahead
* vdev_file_logical_ashift
* vdev_file_physical_ashift
* zfs_arc_dnode_limit
* zfs_arc_dnode_limit_percent
* zfs_arc_dnode_reduce_percent
* zfs_arc_meta_limit_percent
* zfs_arc_sys_free
* zfs_deadman_ziotime_ms
* zfs_delete_blocks
* zfs_history_output_max
* zfs_livelist_max_entries
* zfs_max_async_dedup_frees
* zfs_max_nvlist_src_size
* zfs_rebuild_max_segment
* zfs_rebuild_vdev_limit
* zfs_unflushed_log_txg_max
* zfs_vdev_max_auto_ashift
* zfs_vdev_min_auto_ashift
* zfs_vnops_read_chunk_size
* zvol_max_discard_blocks
Rather than clutter the lists with commentary, the module parameters
that need comments are repeated below.
A few parameters were defined in Linux/FreeBSD specific code, where the
use of ulong/long is not an issue for portability, so we leave them
alone:
* zfs_delete_blocks
* zfs_key_max_salt_uses
* zvol_max_discard_blocks
The documentation for a few parameters was found to be incorrect:
* zfs_deadman_checktime_ms - incorrectly documented as int
* zfs_delete_blocks - not documented as Linux only
* zfs_history_output_max - incorrectly documented as int
* zfs_vnops_read_chunk_size - incorrectly documented as long
* zvol_max_discard_blocks - incorrectly documented as ulong
The documentation for these has been fixed, alongside the changes to
document the switch to fixed width types.
In addition, several kernel module parameters were percentages or held
ashift values, so being 64-bit never made sense for them. They have been
downgraded to 32-bit:
* vdev_file_logical_ashift
* vdev_file_physical_ashift
* zfs_arc_dnode_limit_percent
* zfs_arc_dnode_reduce_percent
* zfs_arc_meta_limit_percent
* zfs_per_txg_dirty_frees_percent
* zfs_unflushed_log_block_pct
* zfs_vdev_max_auto_ashift
* zfs_vdev_min_auto_ashift
Of special note are `zfs_vdev_max_auto_ashift` and
`zfs_vdev_min_auto_ashift`, which were already defined as `uint64_t`,
and passed to the kernel as `ulong`. This is inherently buggy on big
endian 32-bit Linux, since the values would not be written to the
correct locations. 32-bit FreeBSD was unaffected because its sysctl code
correctly treated this as a `uint64_t`.
Lastly, a code comment suggests that `zfs_arc_sys_free` is
Linux-specific, but there is nothing to indicate to me that it is
Linux-specific. Nothing was done about that.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Original-patch-by: Andrew Innes <andrew.c12@gmail.com>
Original-patch-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13984Closes#14004
When there are many snapshots, calls to zfs_ioc_space_snaps() (e.g. from
`zfs destroy -nv pool/fs@snap1%snap10000`) can be very slow, resulting
in poor performance because we are holding the dp_config_rwlock the
entire time, blocking spa_sync() from continuing. With around ten
thousand snapshots, we've seen up to 500 seconds in this ioctl,
iterating over up to 50,000,000 bpobjs, ~99% of which are the empty
bpobj.
By creating a fast path for zfs_ioc_space_snaps() handling of the
empty_bpobj, we can achieve a ~5x performance improvement of this ioctl
(when there are many snapshots, and the deadlist is mostly
empty_bpobj's).
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-58348
Closes#8744
Deleting a clone requires finding blocks are clone-only, not shared
with the snapshot. This was done by traversing the entire block tree
which results in a large performance penalty for sparsely
written clones.
This is new method keeps track of clone blocks when they are
modified in a "Livelist" so that, when it’s time to delete,
the clone-specific blocks are already at hand.
We see performance improvements because now deletion work is
proportional to the number of clone-modified blocks, not the size
of the original dataset.
Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Sara Hartse <sara.hartse@delphix.com>
Closes#8416
OpenZFS 7614 - zfs device evacuation/removal
OpenZFS 9064 - remove_mirror should wait for device removal to complete
This project allows top-level vdevs to be removed from the storage pool
with "zpool remove", reducing the total amount of storage in the pool.
This operation copies all allocated regions of the device to be removed
onto other devices, recording the mapping from old to new location.
After the removal is complete, read and free operations to the removed
(now "indirect") vdev must be remapped and performed at the new location
on disk. The indirect mapping table is kept in memory whenever the pool
is loaded, so there is minimal performance overhead when doing operations
on the indirect vdev.
The size of the in-memory mapping table will be reduced when its entries
become "obsolete" because they are no longer used by any block pointers
in the pool. An entry becomes obsolete when all the blocks that use
it are freed. An entry can also become obsolete when all the snapshots
that reference it are deleted, and the block pointers that reference it
have been "remapped" in all filesystems/zvols (and clones). Whenever an
indirect block is written, all the block pointers in it will be "remapped"
to their new (concrete) locations if possible. This process can be
accelerated by using the "zfs remap" command to proactively rewrite all
indirect blocks that reference indirect (removed) vdevs.
Note that when a device is removed, we do not verify the checksum of
the data that is copied. This makes the process much faster, but if it
were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be
possible to copy the wrong data, when we have the correct data on e.g.
the other side of the mirror.
At the moment, only mirrors and simple top-level vdevs can be removed
and no removal is allowed if any of the top-level vdevs are raidz.
Porting Notes:
* Avoid zero-sized kmem_alloc() in vdev_compact_children().
The device evacuation code adds a dependency that
vdev_compact_children() be able to properly empty the vdev_child
array by setting it to NULL and zeroing vdev_children. Under Linux,
kmem_alloc() and related functions return a sentinel pointer rather
than NULL for zero-sized allocations.
* Remove comment regarding "mpt" driver where zfs_remove_max_segment
is initialized to SPA_MAXBLOCKSIZE.
Change zfs_condense_indirect_commit_entry_delay_ticks to
zfs_condense_indirect_commit_entry_delay_ms for consistency with
most other tunables in which delays are specified in ms.
* ZTS changes:
Use set_tunable rather than mdb
Use zpool sync as appropriate
Use sync_pool instead of sync
Kill jobs during test_removal_with_operation to allow unmount/export
Don't add non-disk names such as "mirror" or "raidz" to $DISKS
Use $TEST_BASE_DIR instead of /tmp
Increase HZ from 100 to 1000 which is more common on Linux
removal_multiple_indirection.ksh
Reduce iterations in order to not time out on the code
coverage builders.
removal_resume_export:
Functionally, the test case is correct but there exists a race
where the kernel thread hasn't been fully started yet and is
not visible. Wait for up to 1 second for the removal thread
to be started before giving up on it. Also, increase the
amount of data copied in order that the removal not finish
before the export has a chance to fail.
* MMP compatibility, the concept of concrete versus non-concrete devices
has slightly changed the semantics of vdev_writeable(). Update
mmp_random_leaf_impl() accordingly.
* Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool
feature which is not supported by OpenZFS.
* Added support for new vdev removal tracepoints.
* Test cases removal_with_zdb and removal_condense_export have been
intentionally disabled. When run manually they pass as intended,
but when running in the automated test environment they produce
unreliable results on the latest Fedora release.
They may work better once the upstream pool import refectoring is
merged into ZoL at which point they will be re-enabled.
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Alex Reece <alex@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
OpenZFS-issue: https://www.illumos.org/issues/7614
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1ebCloses#6900
One of the neat tricks an autoconf style project is capable of
is allow configurion/building in a directory other than the
source directory. The major advantage to this is that you can
build the project various different ways while making changes
in a single source tree.
For example, this project is designed to work on various different
Linux distributions each of which work slightly differently. This
means that changes need to verified on each of those supported
distributions perferably before the change is committed to the
public git repo.
Using nfs and custom build directories makes this much easier.
I now have a single source tree in nfs mounted on several different
systems each running a supported distribution. When I make a
change to the source base I suspect may break things I can
concurrently build from the same source on all the systems each
in their own subdirectory.
wget -c http://github.com/downloads/behlendorf/zfs/zfs-x.y.z.tar.gz
tar -xzf zfs-x.y.z.tar.gz
cd zfs-x-y-z
------------------------- run concurrently ----------------------
<ubuntu system> <fedora system> <debian system> <rhel6 system>
mkdir ubuntu mkdir fedora mkdir debian mkdir rhel6
cd ubuntu cd fedora cd debian cd rhel6
../configure ../configure ../configure ../configure
make make make make
make check make check make check make check
This change also moves many of the include headers from individual
incude/sys directories under the modules directory in to a single
top level include directory. This has the advantage of making
the build rules cleaner and logically it makes a bit more sense.
Richard Yao
Tino Reichardt
Matthew Ahrens
Sara Hartse
Brian Behlendorf