Linux 4.2 commit torvalds/linux@dac5621 renamed bio->bi_cnt to
bio->__bi_cnt. Because this value is only used once in a block of
debug code it simplest just to remove the PANIC. To my knowledge
this debugging has never been hit or proved useful so this is no
great loss.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes#3596
The vfs_compat.h header should include the linux/backing-dev.h header
because it depends on the bdi_* functions defined there. In previous
kernels this header was being indirectly included which prevented a
build failure.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes#3596
Many key internal functions pass system return codes that are safe to
return to userland. In the case of ddi_copyin(9F), an error passes -1
and the documentation states very clearly that drivers should pass
EFAULT to userland when this happens.
http://illumos.org/man/9F/ddi_copyin
This does not happen in the ZFS source code. I believe it should be
changed to pass EFAULT. I caught this when writing man pages for the
libzfs_core API.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3575
Translate zio requests with ZIO_PRIORITY_SYNC_READ and
ZIO_PRIORITY_SYNC_WRITE into synchronous bio requests by setting
READ_SYNC and WRITE_SYNC flags. Specifically, WRITE_SYNC flag turns
out to have a pronounced effect when writing to an SSD-based SLOG.
When WRITE_SYNC is not set (WRITE is set instead), the block trace
for a SLOG device looks as follows:
...
130,96 0 3 0.008968390 0 C W 830464 + 136 [0]
130,96 0 4 0.011999161 0 C W 830720 + 136 [0]
130,96 0 5 0.023955549 0 C W 831744 + 136 [0]
130,96 0 6 0.024337663 19775 A W 832000 + 136 <- (130,97) 829952
130,96 0 7 0.024338823 19775 Q W 832000 + 136 [z_wr_iss/6]
130,96 0 8 0.024340523 19775 G W 832000 + 136 [z_wr_iss/6]
130,96 0 9 0.024343187 19775 P N [z_wr_iss/6]
130,96 0 10 0.024344120 19775 I W 832000 + 136 [z_wr_iss/6]
130,96 0 11 0.026784405 0 UT N [swapper] 1
130,96 0 12 0.026805339 202 U N [kblockd/0] 1
130,96 0 13 0.026807199 202 D W 832000 + 136 [kblockd/0]
130,96 0 14 0.026966948 0 C W 832000 + 136 [0]
130,96 3 1 0.000449358 19788 A W 829952 + 136 <- (130,97) 827904
130,96 3 2 0.000450951 19788 Q W 829952 + 136 [z_wr_iss/19]
130,96 3 3 0.000453212 19788 G W 829952 + 136 [z_wr_iss/19]
130,96 3 4 0.000455956 19788 P N [z_wr_iss/19]
130,96 3 5 0.000457076 19788 I W 829952 + 136 [z_wr_iss/19]
130,96 3 6 0.002786349 0 UT N [swapper] 1
...
Here the 130,197 is the partition created on the log device when adding it
to the pool, whereas the base device is 130,96. As one can see, the writes
to the SLOG are not marked synchronous (the S is missing next to W), and
the queue unplugs occur based on the timer (UT event) resulting in slightly
over 2 msec latency of writes. This results in a sub-par performance of
single stream synchronous writes (limited by latency of the SLOG).
When the WRITE_SYNC is set, a similar trace looks as follows:
...
130,96 4 1 0.000000000 70714 A WS 4280576 + 136 <- (130,97) 4278528
130,96 4 2 0.000000832 70714 Q WS 4280576 + 136 [(null)]
130,96 4 3 0.000002109 70714 G WS 4280576 + 136 [(null)]
130,96 4 4 0.000003394 70714 P N [(null)]
130,96 4 5 0.000003846 70714 I WS 4280576 + 136 [(null)]
130,96 4 6 0.000004854 70714 D WS 4280576 + 136 [(null)]
130,96 5 1 0.000354487 70713 A WS 4280832 + 136 <- (130,97) 4278784
130,96 5 2 0.000355072 70713 Q WS 4280832 + 136 [(null)]
130,96 5 3 0.000356383 70713 G WS 4280832 + 136 [(null)]
130,96 5 4 0.000357635 70713 P N [(null)]
130,96 5 5 0.000358088 70713 I WS 4280832 + 136 [(null)]
130,96 5 6 0.000359191 70713 D WS 4280832 + 136 [(null)]
130,96 0 76 0.000159539 0 C WS 4280576 + 136 [0]
130,96 16 85 0.000742108 70718 A WS 4281088 + 136 <- (130,97) 4279040
130,96 16 86 0.000743197 70718 Q WS 4281088 + 136 [z_wr_iss/15]
130,96 16 87 0.000744450 70718 G WS 4281088 + 136 [z_wr_iss/15]
130,96 16 88 0.000745817 70718 P N [z_wr_iss/15]
130,96 16 89 0.000746705 70718 I WS 4281088 + 136 [z_wr_iss/15]
130,96 16 90 0.000747848 70718 D WS 4281088 + 136 [z_wr_iss/15]
130,96 0 77 0.000604063 0 C WS 4280832 + 136 [0]
130,96 0 78 0.000899858 0 C WS 4281088 + 136 [0]
As one can see, all the writes are synchronous (WS), and I/O completions
(e.g. from issue I to completion C) take 160-250 usec, or about 10x faster.
Since WRITE_SYNC or READ_SYNC flags are among several factors that are
considered when processing bio requests, it seems prudent to mark all the
zio requests of synchronous priority with the READ/WRITE_SYNC flags to make
them eligible for consideration as such by the Linux block I/O layer.
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3529
As of gcc version 5.1.1 a new warning has been added to detect the
use of a boolean in a switch statement (-Wswitch-bool). Resolve the
warning by explicitly casting the value to an integer type.
zfs-0.6.4/module/zfs/zvol.c: In function 'zvol_request':
error: switch condition has boolean value [-Werror=switch-bool]
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
As of gcc version 5.1.1 a new boolean comparison warning has been
introduced. This warning is harmless but is triggered several places
in the ZFS code base. Because warnings are promoted to errors when
building with debugging enabled it is necessary to disable the warning
when using versions of gcc which automatically enabling this check.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
For the purposes of creating sparse files the truncate command is
preferable to fallocate because generic sparse files are more widely
supported by older platforms. Specifically Debian Wheezy which is
based on a 2.6.32 kernel used ext3 by default which at the time did
not support it.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
We fail to make partitions on xvd (Xen Virtual Block) devices. This also
causes debug builds of zpool create to return an error when given xen
virtual block devices. These devices should be given the same treatment
as vd (KVM Virtual Block) devices, so we adjust the relevant code paths.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3576
5661 ZFS: "compression = on" should use lz4 if feature is enabled
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Reviewed by: Xin LI <delphij@freebsd.org>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://github.com/illumos/illumos-gate/commit/db1741fhttps://www.illumos.org/issues/5661
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3571
5118 When verifying or creating a storage pool, error messages
only show one device
Reviewed by: Adam Leventhal <adam.leventhal@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Boris Protopopov <boris.protopopov@me.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://github.com/illumos/illumos-gate/commit/75fbdf9https://www.illumos.org/issues/5118
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3567
4966 zpool list iterator does not update output
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
https://github.com/illumos/illumos-gate/commit/cd67d23https://www.illumos.org/issues/4966
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3566
The dracut code is analogous to the initramfs code and as such
it should be located in the contrib with initramfs for consistency.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
* Supports booting of a ZFS snapshot.
Do this by cloning the snapshot into a dataset. If this, the resulting
dataset, already exists, destroy it. Then mount it on root.
* If snapshot does not exist, use base dataset (the part before '@')
as boot filesystem instead.
* If no snapshot is specified on the 'root=' kernel command line, but there
is an '@', then get a list of snapshots below that filesystem and ask the
user which to use.
* Clone with 'mountpoint=none' and 'canmount=noauto' - we mount manually
and explicitly.
* For sub-filesystems, that doesn't have a mountpoint property set, we use
the 'org.zol:mountpoint' to keep track of it's mountpoint.
* Allow rollback of snapshots instead of clone it and boot from the clone.
* Allow mounting a root- and subfs with mountpoint=legacy set
* Allow mounting a filesystem which is using nativ encryption.
* Support all currently used kernel command line arguments
All the different distributions have their own standard on what to specify
on the kernel command line to boot of a ZFS filesystem.
* Extra options:
* zfsdebug=(on,yes,1) Show extra debugging information
* zfsforce=(on,yes,1) Force import the pool
* rollback=(on,yes,1) Rollback (instead of clone) the snapshot
* Only try to import pool if it haven't already been imported
* This will negate the need to force import a pool that have not been exported cleanly.
* Support exclusion of pools to import by setting ZFS_POOL_EXCEPTIONS in /etc/default/zfs.
* Support additional configuration variable ZFS_INITRD_ADDITIONAL_DATASETS
to mount additional filesystems not located under your root dataset.
* Include /etc/modprobe.d/{zfs,spl}.conf in the initrd if it/they exist.
* Include the udev rule to use by-vdev for pool imports.
* Include the /etc/default/zfs file to the initrd.
* Only try /dev/disk/by-* in the initrd if USE_DISK_BY_ID is set.
* Use /dev/disk/by-vdev before anything.
* Add /dev as a last ditch attempt.
* Fallback to using the cache file if that exist if nothing else worked.
* Use /sbin/modprobe instead of built-in (BusyBox) modprobe.
This gets rid of the message "modprobe: can't load module zcommon".
Thanx to pcoultha for finding this.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2116Closes#2114
Reclaim during metaslab preloading can cause deadlocks involving znode
z_lock and ARC buffer header ht_lock.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3532.
5008 lock contention (rrw_exit) while running a read only load
Reviewed by: Matthew Ahrens <matthew.ahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Richard Yao <ryao@gentoo.org>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Approved by: Garrett D'Amore <garrett@damore.org>
Porting notes:
This patch ported perfectly cleanly to ZoL. During testing 100% cached
small-block reads, extreme contention was noticed on rrl->rr_lock from
rrw_exit() due to the frequent entering and leaving ZPL. Illumos picked
up this patch from FreeBSD and it also helps under Linux.
On a 1-minute 4K cached read test with 10 fio processes pinned to a single
socket on a 4-socket (10 thread per socket) NUMA system, contentions on
rrl->rr_lock were reduced from 508799 to 43085.
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3555
5946 zfs_ioc_space_snaps must check that firstsnap and lastsnap refer to snapshots
5945 zfs_ioc_send_space must ensure that fromsnap refers to a snapshot
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gordon.ross@nexenta.com>
References:
https://www.illumos.org/issues/5946https://www.illumos.org/issues/5945https://github.com/illumos/illumos-gate/commit/24218be
Ported-by: Andriy Gapon <avg@FreeBSD.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3552
5909 ensure that shared snap names don't become too long after promotion
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5909https://github.com/illumos/illumos-gate/commit/cb5842f
Ported-by: Andriy Gapon <avg@FreeBSD.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3550
5912 full stream can not be force-received into a dataset if it has a snapshot
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5912https://github.com/illumos/illumos-gate/commit/5bae108
Ported-by: Andriy Gapon <avg@FreeBSD.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3549
A few minor mistakes than should be fixed:
zpool:
compatability -> compatibility
zfs:
accessable -> accessible
availible -> available
zfs-events:
availible -> available
zfs-module-parameters:
proceding -> proceeding
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3544
5175 implement dmu_read_uio_dbuf() to improve cached read performance
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Richard Elling <richard.elling@gmail.com>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5175https://github.com/illumos/illumos-gate/commit/f8554bb
Porting notes:
This patch doesn't include the changes for the COMSTAR (Common
Multiprotocol SCSI Target) - since it's not available for ZoL.
http://thegreyblog.blogspot.co.at/2010/02/setting-up-solaris-comstar-and.html
Ported by: kernelOfTruth <kerneloftruth@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3392
This is especially needed when using LUKS backed pools.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3536
Illumos 5701 (zpool list reports incorrect "alloc" value for cache
devices) removed l2ad_evict from l2arc_dev_t. It should also be removed
from the zfs_l2arc_evict_class event class.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3534
The ziltest.sh script is a test case designed to verify the correct
functioning of the ZIL. It's being added to the scripts directory
so it can be easily added to the automated regression testing.
The general idea is to build up an intent log from a bunch of
diverse user commands without actually committing them to the file
system. Then copy the file system, replay the intent log and
compare the file system and the copy.
Ported-by: Don Brady <don.brady@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3531
Allocating SPA_MAXBLOCKSIZE on the stack is a bad idea (even with the
old 128K size). Use malloc instead when allocating temporary block
buffer memory.
Signed-off-by: Don Brady <don.brady@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3522
Skip large blocks feature refcount checking if feature is disabled.
Signed-off-by: Don Brady <don.brady@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3468
* In read_mtab(), fix problems (!?) in the mounts file. It will record
'rpool 1' as 'rpool\0401' instead of 'rpool\00401' which seems to be the
correct (at least as far as 'printf' is concerned). Use this using the
external 'echo' command (and not the one built in to the shell) because
the internal one would interpret the backslash code (incorrectly), giving
us a instead.
* Remove reregister_mounts() - no longer needed.
* For Gentoo, the zfs_log_failure_msg() should use eend(), not eerror()
(which requires an error message, which we don't have).
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3488Closes#3509Closes#3514
This reverts commit 036391c980.
Because #3509 came just after this commit was accepted and is related
to the original problem the commit was supposed to fix, we need to
solve the problem in another way.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5368 ARC should cache more metadata
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5368https://github.com/illumos/illumos-gate/commit/3a5286a
Porting Notes:
The vast majority of this patch was already merged in the context
of the 06358ea changes. This is just a small hunk which was missed.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
5163 arc should reap range_seg_cache
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@gmail.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5163https://github.com/illumos/illumos-gate/commit/83803b5
Porting Notes:
Added umem_cache_reap_now() wrapped to suppress unused variable
warning for user space build in arc_kmem_reap_now().
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Over the years the default values for the taskqs used on Linux have
differed slightly from illumos. In the vast majority of cases this
was done to avoid creating an obnoxious number of idle threads which
would pollute the process listing.
With the addition of support for dynamic taskqs all multi-threaded
queues should be created as dynamic taskqs. This allows us to get
the best of both worlds.
* The illumos default values for the I/O pipeline can be restored.
These values are known to work well for most workloads. The only
exception is the zio write interrupt taskq which is changed to
ZTI_P(12, 8). At least under Linux more threads has been shown
to improve performance, see commit 7e55f4e.
* Reduces the number of idle threads on the system when it's not
under heavy load. The maximum number of threads will only be
created when they are required.
* Remove the vdev_file_taskq and rely on the system_taskq instead
which is now dynamic and may have up to 64-threads. Again this
brings us back inline with upstream.
* Tasks dispatched with taskq_dispatch_ent() are allowed to use
dynamic taskqs. The Linux taskq implementation supports this.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#3507
If we don't account for that, then we might end up overwriting disk
area of buffers that have not been evicted yet, because l2arc_evict
operates in terms of disk addresses.
The discrepancy between the write size calculation and the actual
increment to l2ad_hand was introduced in commit 3a17a7a9.
The change that introduced l2ad_hand alignment was almost correct
as the write size was accumulated as a sum of rounded buffer sizes.
See commit illumos/illumos-gate@e14bb32.
Also, we now consistently use asize / a_sz for the allocated size and
psize / p_sz for the physical size. The latter accounts for a
possible size reduction because of the compression, whereas the
former accounts for a possible subsequent size expansion because of
the alignment requirements.
The code still assumes that either underlying storage subsystems or
hardware is able to do read-modify-write when an L2ARC buffer size is
not a multiple of a disk's block size. This is true for 4KB sector disks
that provide 512B sector emulation, but may not be true in general.
In other words, we currently do not have any code to make sure that
an L2ARC buffer, whether compressed or not, which is used for physical
I/O has a suitable size.
Note that currently the cache device utilization is calculated based
on the physical size, not the allocated size. The same applies to
l2_asize kstat. That is wrong, but this commit does not fix that.
The accounting problem was introduced partially in commit 3a17a7a9
and partially in 3038a2b (accounting became consistent but in favour
of the wrong size).
Porting Notes:
Reworked to be C90 compatible and the 'write_psize' variable was
removed because it is now unused.
References:
https://reviews.csiden.org/r/229/https://reviews.freebsd.org/D2764
Ported-by: kernelOfTruth <kerneloftruth@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3400Closes#3433Closes#3451
Added for upstream compatibility, they are of the form:
* IMPLY(a, b) - if (a) then (b)
* EQUIV(a, b) - if (a) then (b) *AND* if (b) then (a)
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Unit testing at ClusterHQ found that passing an invalid file handle to
zfs_ioc_hold results in a NULL pointer dereference on a system without
assertions:
IP: [<ffffffffa0218aa0>] zfsdev_getminor+0x10/0x20 [zfs]
Call Trace:
[<ffffffffa021b4b0>] zfs_onexit_fd_hold+0x20/0x40 [zfs]
[<ffffffffa0214043>] zfs_ioc_hold+0x93/0xd0 [zfs]
[<ffffffffa0215890>] zfsdev_ioctl+0x200/0x500 [zfs]
An assertion would have caught this had they been enabled, but this is
something that the kernel module should handle without failing. We
resolve this by searching the linked list to ensure that the file
handle's private_data points to a valid zfsdev_state_t.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Andriy Gapon <avg@FreeBSD.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3506
This seems generally useful. metaslab_aliquot is the ZFS allocation
granularity, which is roughly equivalent to what is called the stripe
size in traditional RAID arrays. It seems relevant to performance
tuning.
Signed-off-by: Etienne Dechamps <etienne@edechamps.fr>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The metaslab allocator device selection algorithm contains a bias
mechanism whose goal is to achieve roughly equal disk space usage across
all top-level vdevs.
It seems that the initial rationale for this code was to allow newly
added (empty) vdevs to "come up to speed" faster in an attempt to make
the pool quickly converge to a steady state where all vdevs are equally
utilized.
While the code seems to work reasonably well for this use case, there
is another scenario in which this algorithm fails miserably: the case
where top-level vdevs don't have the same sizes (capacities). ZFS
allows this, and it is a good feature to have, so that users who simply
want to build a pool with the disks they happen to have lying around can
do so even if the disks have heteregenous sizes.
Here's a script that simulates a pool with two vdevs, with one 4X larger
than the other:
dd if=/dev/zero of=/tmp/d1 bs=1 count=1 seek=134217728
dd if=/dev/zero of=/tmp/d2 bs=1 count=1 seek=536870912
zpool create testspace /tmp/d1 /tmp/d2
dd if=/dev/zero of=/testspace/foobar bs=1M count=256
zpool iostat -v testspace
Before this commit, the script would output the following:
capacity
pool alloc free
---------- ----- -----
testspace 252M 375M
/tmp/d1 104M 18.5M
/tmp/d2 148M 356M
---------- ----- -----
This demonstrates that the current code handles this situation very
poorly: d1 shows 85% usage despite the pool itself being only 40% full.
d1 is quite saturated at this point, and is slowing down the entire pool
due to saturation, fragmentation and the like.
In contrast, here's the result with the code in this commit:
capacity
pool alloc free
---------- ----- -----
testspace 252M 375M
/tmp/d1 56.7M 66.3M
/tmp/d2 195M 309M
---------- ----- ------
This looks much better. d1 is 46% used, which is close to the overall
pool utilization (40%). The code still doesn't result in perfectly
balanced allocation, probably because of the way mg_bias is applied
which does not guarantee perfect accuracy, but this is still much better
than before.
Signed-off-by: Etienne Dechamps <etienne@edechamps.fr>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3389
For kernels which do not implement a per-suberblock shrinker,
those older than Linux 3.1, the shrink_dcache_parent() function
was used to attempt to reclaim dentries. This was found not be
entirely reliable and could lead to performance issues on older
kernels running meta-data heavy workloads.
To address this issue a zfs_sb_prune_aliases() function has been
added to implement this functionality. It relies on traversing
the list of znodes for a filesystem and adding them to a private
list with a reference held. The private list can then be safely
walked outside the z_znodes_lock to prune dentires and drop the
last reference so the inode can be freed.
This provides the same synchronous behavior as the per-filesystem
shrinker and has the advantage of depending on only long standing
interfaces.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#3501
Brian Behlendorf
Matthew Ahrens
Manoj Joseph
Alexander Eremin
Prasad Joshi
Richard Yao
Boris Protopopov
Richard Yao
Will Andrews
Justin T. Gibbs
Jan Kryl
Basil Crow
George Wilson
Josef 'Jeff' Sipek
Turbo Fredriksson
Tim Chase
Alexander Motin
Arne Jansen
Andriy Gapon
Alek Pinchuk
Colin Ian King
Don Brady
Prakash Surya
Etienne Dechamps