[ZFS] continuous write to disk by zfskern
Yoshiaki Kasahara
kasahara at nc.kyushu-u.ac.jp
Fri Sep 13 09:29:17 UTC 2013
Hello,
Recently I noticed that my (zfs only) FreeBSD 9-STABLE system (for my
main desktop) was very sluggish, and realized that zfskern was
continuously writing something to my main raidz1 pool. By checking my
munin record, it started just after I updated my world on Aug
27th. The temperature of HDD's are kept over 60C and I'm afraid the
system is grinding the lifetime of them rapidly to death.
Only the raidz pool "zroot" shows the symptom. It happens even when
the system is in single user mode.
-----
% zpool iostat 1
capacity operations bandwidth
pool alloc free read write read write
---------- ----- ----- ----- ----- ----- -----
backup2 1.36T 1.36T 0 0 4.60K 2.52K
zroot 1.26T 1.44T 16 1.35K 238K 5.17M
---------- ----- ----- ----- ----- ----- -----
backup2 1.36T 1.36T 0 0 0 0
zroot 1.26T 1.44T 0 1.56K 0 7.96M
---------- ----- ----- ----- ----- ----- -----
backup2 1.36T 1.36T 0 0 0 0
zroot 1.26T 1.44T 0 1.58K 0 4.47M
---------- ----- ----- ----- ----- ----- -----
backup2 1.36T 1.36T 0 0 0 0
zroot 1.26T 1.44T 0 1.59K 0 4.54M
---------- ----- ----- ----- ----- ----- -----
backup2 1.36T 1.36T 0 0 0 0
zroot 1.26T 1.44T 0 1.73K 0 6.13M
---------- ----- ----- ----- ----- ----- -----
^C
% top -mio -SH -owrite 10
last pid: 13351; load averages: 1.04, 0.52, 0.40 up 0+00:30:32 17:55:32
671 processes: 9 running, 635 sleeping, 2 zombie, 25 waiting
Mem: 747M Active, 235M Inact, 1383M Wired, 2100K Cache, 13G Free
ARC: 956M Total, 258M MFU, 661M MRU, 5566K Anon, 8027K Header, 23M Other
Swap: 24G Total, 24G Free
PID USERNAME VCSW IVCSW READ WRITE FAULT TOTAL PERCENT COMMAND
4 root 129929 114 229 166157 0 166386 88.64% zfskern{txg_
1198 root 751 15 15 1621 0 1636 0.87% syslogd
1025 _pflogd 5642 2 1 1390 0 1391 0.74% pflogd
2512 kasahara 120297 1606 116 574 182 872 0.46% Xorg
2569 kasahara 1131 21 712 196 8 916 0.49% gconfd-2
2598 www 136 0 4 146 0 150 0.08% httpd
2570 www 192 4 12 143 0 155 0.08% httpd
2248 www 147 4 19 141 0 160 0.09% httpd
2626 kasahara 4192 91 381 131 389 901 0.48% nautilus{nau
4536 kasahara 32937 762 1866 128 725 2719 1.45% emacs-24.3.5
-----
Are there any way to see what is happening to my system? I had I
believe the behavior started to happen when I installed the following
kernel, but I'm not sure if it is a culprit.
FreeBSD 9.2-PRERELEASE #0 r254947: Tue Aug 27 13:36:54 JST 2013
I updated my world again after that (to fix vulnerabilities), so I
don't have the previous kernel anymore. I can only remember the
previous update was during July.
My system has two pools, one is raidz consist of 3 disks, another one
is single disk pool. Please ignore backup2's data errors (it is
another story and I'm going to replace the disk soon).
-----
% zpool status
pool: backup2
state: ONLINE
status: One or more devices has experienced an error resulting in data
corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the
entire pool from backup.
see: http://illumos.org/msg/ZFS-8000-8A
scan: scrub repaired 0 in 3h37m with 9 errors on Sat Aug 31 08:34:28 2013
config:
NAME STATE READ WRITE CKSUM
backup2 ONLINE 0 0 0
gpt/backup2 ONLINE 0 0 0
errors: 9 data errors, use '-v' for a list
pool: zroot
state: ONLINE
scan: scrub canceled on Fri Sep 13 17:22:45 2013
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
gpt/disk0 ONLINE 0 0 0
gpt/disk1 ONLINE 0 0 0
gpt/disk2 ONLINE 0 0 0
errors: No known data errors
% grep ada /var/run/dmesg.boot
ada0 at ahcich0 bus 0 scbus0 target 0 lun 0
ada0: <Hitachi HUA721010KLA330 GKAOAB0A> ATA-7 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada0: Command Queueing enabled
ada0: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
ada0: Previously was known as ad4
ada1 at ahcich1 bus 0 scbus1 target 0 lun 0
ada1: <Hitachi HUA721010KLA330 GKAOAB0A> ATA-7 SATA 2.x device
ada1: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada1: Command Queueing enabled
ada1: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
ada1: Previously was known as ad6
ada2 at ahcich2 bus 0 scbus2 target 0 lun 0
ada2: <Hitachi HUA721010KLA330 GKAOAB0A> ATA-7 SATA 2.x device
ada2: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada2: Command Queueing enabled
ada2: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
ada2: Previously was known as ad8
ada3 at ahcich4 bus 0 scbus4 target 0 lun 0
ada3: <ST3000DM001-9YN166 CC4H> ATA-8 SATA 3.x device
ada3: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada3: Command Queueing enabled
ada3: 2861588MB (5860533168 512 byte sectors: 16H 63S/T 16383C)
ada3: quirks=0x1<4K>
ada3: Previously was known as ad12
% gpart list
Geom name: ada0
modified: false
state: OK
fwheads: 16
fwsectors: 63
last: 1953525134
first: 34
entries: 128
scheme: GPT
Providers:
1. Name: ada0p1
Mediasize: 65536 (64k)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 17408
Mode: r0w0e0
rawuuid: 5c629775-10e5-11df-9abf-001b21525260
rawtype: 83bd6b9d-7f41-11dc-be0b-001560b84f0f
label: (null)
length: 65536
offset: 17408
type: freebsd-boot
index: 1
end: 161
start: 34
2. Name: ada0p2
Mediasize: 8589934592 (8.0G)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 82944
Mode: r1w1e1
rawuuid: 9f7ec4c5-10e5-11df-9abf-001b21525260
rawtype: 516e7cb5-6ecf-11d6-8ff8-00022d09712b
label: swap0
length: 8589934592
offset: 82944
type: freebsd-swap
index: 2
end: 16777377
start: 162
3. Name: ada0p3
Mediasize: 991614851584 (923G)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 82944
Mode: r1w1e2
rawuuid: d275a596-10e5-11df-9abf-001b21525260
rawtype: 516e7cba-6ecf-11d6-8ff8-00022d09712b
label: disk0
length: 991614851584
offset: 8590017536
type: freebsd-zfs
index: 3
end: 1953525134
start: 16777378
Consumers:
1. Name: ada0
Mediasize: 1000204886016 (931G)
Sectorsize: 512
Mode: r2w2e5
Geom name: ada1
modified: false
state: OK
fwheads: 16
fwsectors: 63
last: 1953525134
first: 34
entries: 128
scheme: GPT
Providers:
1. Name: ada1p1
Mediasize: 65536 (64k)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 17408
Mode: r0w0e0
rawuuid: 5f353ff1-10e5-11df-9abf-001b21525260
rawtype: 83bd6b9d-7f41-11dc-be0b-001560b84f0f
label: (null)
length: 65536
offset: 17408
type: freebsd-boot
index: 1
end: 161
start: 34
2. Name: ada1p2
Mediasize: 8589934592 (8.0G)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 82944
Mode: r1w1e1
rawuuid: a28e75bb-10e5-11df-9abf-001b21525260
rawtype: 516e7cb5-6ecf-11d6-8ff8-00022d09712b
label: swap1
length: 8589934592
offset: 82944
type: freebsd-swap
index: 2
end: 16777377
start: 162
3. Name: ada1p3
Mediasize: 991614851584 (923G)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 82944
Mode: r1w1e2
rawuuid: d60cd5c7-10e5-11df-9abf-001b21525260
rawtype: 516e7cba-6ecf-11d6-8ff8-00022d09712b
label: disk1
length: 991614851584
offset: 8590017536
type: freebsd-zfs
index: 3
end: 1953525134
start: 16777378
Consumers:
1. Name: ada1
Mediasize: 1000204886016 (931G)
Sectorsize: 512
Mode: r2w2e5
Geom name: ada2
modified: false
state: OK
fwheads: 16
fwsectors: 63
last: 1953525134
first: 34
entries: 128
scheme: GPT
Providers:
1. Name: ada2p1
Mediasize: 65536 (64k)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 17408
Mode: r0w0e0
rawuuid: 60568cdf-10e5-11df-9abf-001b21525260
rawtype: 83bd6b9d-7f41-11dc-be0b-001560b84f0f
label: (null)
length: 65536
offset: 17408
type: freebsd-boot
index: 1
end: 161
start: 34
2. Name: ada2p2
Mediasize: 8589934592 (8.0G)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 82944
Mode: r1w1e1
rawuuid: a4cfd93f-10e5-11df-9abf-001b21525260
rawtype: 516e7cb5-6ecf-11d6-8ff8-00022d09712b
label: swap2
length: 8589934592
offset: 82944
type: freebsd-swap
index: 2
end: 16777377
start: 162
3. Name: ada2p3
Mediasize: 991614851584 (923G)
Sectorsize: 512
Stripesize: 0
Stripeoffset: 82944
Mode: r1w1e2
rawuuid: d88a0a46-10e5-11df-9abf-001b21525260
rawtype: 516e7cba-6ecf-11d6-8ff8-00022d09712b
label: disk2
length: 991614851584
offset: 8590017536
type: freebsd-zfs
index: 3
end: 1953525134
start: 16777378
Consumers:
1. Name: ada2
Mediasize: 1000204886016 (931G)
Sectorsize: 512
Mode: r2w2e5
Geom name: ada3
modified: false
state: OK
fwheads: 16
fwsectors: 63
last: 5860533134
first: 34
entries: 128
scheme: GPT
Providers:
1. Name: ada3p1
Mediasize: 65536 (64k)
Sectorsize: 512
Stripesize: 4096
Stripeoffset: 0
Mode: r0w0e0
rawuuid: b995fc9e-abc3-11e2-b146-001cc0fac46a
rawtype: 83bd6b9d-7f41-11dc-be0b-001560b84f0f
label: (null)
length: 65536
offset: 20480
type: freebsd-boot
index: 1
end: 167
start: 40
2. Name: ada3p2
Mediasize: 3000591450112 (2.7T)
Sectorsize: 512
Stripesize: 4096
Stripeoffset: 0
Mode: r1w1e2
rawuuid: fcaac211-abc3-11e2-b146-001cc0fac46a
rawtype: 516e7cba-6ecf-11d6-8ff8-00022d09712b
label: backup2
length: 3000591450112
offset: 1048576
type: freebsd-zfs
index: 2
end: 5860532223
start: 2048
Consumers:
1. Name: ada3
Mediasize: 3000592982016 (2.7T)
Sectorsize: 512
Stripesize: 4096
Stripeoffset: 0
Mode: r1w1e3
% zfs-stats -a
------------------------------------------------------------------------
ZFS Subsystem Report Fri Sep 13 18:03:32 2013
------------------------------------------------------------------------
System Information:
Kernel Version: 902503 (osreldate)
Hardware Platform: amd64
Processor Architecture: amd64
ZFS Storage pool Version: 5000
ZFS Filesystem Version: 5
FreeBSD 9.2-PRERELEASE #0 r255506: Fri Sep 13 16:09:51 JST 2013 root
6:03PM up 39 mins, 5 users, load averages: 0.21, 0.32, 0.33
------------------------------------------------------------------------
System Memory:
4.74% 751.62 MiB Active, 1.49% 236.12 MiB Inact
8.89% 1.38 GiB Wired, 0.01% 2.05 MiB Cache
84.86% 13.14 GiB Free, 0.01% 1.84 MiB Gap
Real Installed: 16.00 GiB
Real Available: 99.79% 15.97 GiB
Real Managed: 96.96% 15.48 GiB
Logical Total: 16.00 GiB
Logical Used: 16.44% 2.63 GiB
Logical Free: 83.56% 13.37 GiB
Kernel Memory: 1.10 GiB
Data: 97.02% 1.07 GiB
Text: 2.98% 33.62 MiB
Kernel Memory Map: 15.47 GiB
Size: 6.44% 1019.41 MiB
Free: 93.56% 14.47 GiB
------------------------------------------------------------------------
ARC Summary: (HEALTHY)
Memory Throttle Count: 0
ARC Misc:
Deleted: 25
Recycle Misses: 0
Mutex Misses: 0
Evict Skips: 744
ARC Size: 15.90% 977.06 MiB
Target Size: (Adaptive) 100.00% 6.00 GiB
Min Size (Hard Limit): 16.67% 1.00 GiB
Max Size (High Water): 6:1 6.00 GiB
ARC Size Breakdown:
Recently Used Cache Size: 50.00% 3.00 GiB
Frequently Used Cache Size: 50.00% 3.00 GiB
ARC Hash Breakdown:
Elements Max: 31.89k
Elements Current: 100.00% 31.89k
Collisions: 107.00k
Chain Max: 4
Chains: 1.83k
------------------------------------------------------------------------
ARC Efficiency: 1.19m
Cache Hit Ratio: 97.73% 1.16m
Cache Miss Ratio: 2.27% 26.98k
Actual Hit Ratio: 92.39% 1.10m
Data Demand Efficiency: 97.97% 531.13k
Data Prefetch Efficiency: 17.48% 1.84k
CACHE HITS BY CACHE LIST:
Anonymously Used: 5.46% 63.35k
Most Recently Used: 26.05% 302.29k
Most Frequently Used: 68.50% 795.00k
Most Recently Used Ghost: 0.00% 0
Most Frequently Used Ghost: 0.00% 0
CACHE HITS BY DATA TYPE:
Demand Data: 44.83% 520.37k
Prefetch Data: 0.03% 322
Demand Metadata: 49.71% 576.91k
Prefetch Metadata: 5.43% 63.04k
CACHE MISSES BY DATA TYPE:
Demand Data: 39.89% 10.76k
Prefetch Data: 5.63% 1.52k
Demand Metadata: 27.09% 7.31k
Prefetch Metadata: 27.39% 7.39k
------------------------------------------------------------------------
L2ARC is disabled
------------------------------------------------------------------------
File-Level Prefetch: (HEALTHY)
DMU Efficiency: 2.98m
Hit Ratio: 74.29% 2.22m
Miss Ratio: 25.71% 766.97k
Colinear: 766.97k
Hit Ratio: 0.01% 98
Miss Ratio: 99.99% 766.87k
Stride: 2.18m
Hit Ratio: 100.00% 2.18m
Miss Ratio: 0.00% 6
DMU Misc:
Reclaim: 766.87k
Successes: 0.52% 4.01k
Failures: 99.48% 762.86k
Streams: 32.42k
+Resets: 0.10% 34
-Resets: 99.90% 32.39k
Bogus: 0
------------------------------------------------------------------------
VDEV cache is disabled
------------------------------------------------------------------------
ZFS Tunables (sysctl):
kern.maxusers 1357
vm.kmem_size 16622653440
vm.kmem_size_scale 1
vm.kmem_size_min 0
vm.kmem_size_max 329853485875
vfs.zfs.arc_max 6442450944
vfs.zfs.arc_min 1073741824
vfs.zfs.arc_meta_used 246149616
vfs.zfs.arc_meta_limit 4294967296
vfs.zfs.l2arc_write_max 8388608
vfs.zfs.l2arc_write_boost 8388608
vfs.zfs.l2arc_headroom 2
vfs.zfs.l2arc_feed_secs 1
vfs.zfs.l2arc_feed_min_ms 200
vfs.zfs.l2arc_noprefetch 1
vfs.zfs.l2arc_feed_again 1
vfs.zfs.l2arc_norw 1
vfs.zfs.anon_size 3833856
vfs.zfs.anon_metadata_lsize 0
vfs.zfs.anon_data_lsize 0
vfs.zfs.mru_size 694739968
vfs.zfs.mru_metadata_lsize 115806208
vfs.zfs.mru_data_lsize 529095680
vfs.zfs.mru_ghost_size 28662784
vfs.zfs.mru_ghost_metadata_lsize 13669888
vfs.zfs.mru_ghost_data_lsize 14992896
vfs.zfs.mfu_size 289340928
vfs.zfs.mfu_metadata_lsize 26335232
vfs.zfs.mfu_data_lsize 249390592
vfs.zfs.mfu_ghost_size 72080896
vfs.zfs.mfu_ghost_metadata_lsize 41472
vfs.zfs.mfu_ghost_data_lsize 72039424
vfs.zfs.l2c_only_size 0
vfs.zfs.dedup.prefetch 1
vfs.zfs.nopwrite_enabled 1
vfs.zfs.mdcomp_disable 0
vfs.zfs.no_write_throttle 0
vfs.zfs.write_limit_shift 3
vfs.zfs.write_limit_min 33554432
vfs.zfs.write_limit_max 2142888448
vfs.zfs.write_limit_inflated 51429322752
vfs.zfs.write_limit_override 0
vfs.zfs.prefetch_disable 0
vfs.zfs.zfetch.max_streams 8
vfs.zfs.zfetch.min_sec_reap 2
vfs.zfs.zfetch.block_cap 256
vfs.zfs.zfetch.array_rd_sz 1048576
vfs.zfs.top_maxinflight 32
vfs.zfs.resilver_delay 2
vfs.zfs.scrub_delay 4
vfs.zfs.scan_idle 50
vfs.zfs.scan_min_time_ms 1000
vfs.zfs.free_min_time_ms 1000
vfs.zfs.resilver_min_time_ms 3000
vfs.zfs.no_scrub_io 0
vfs.zfs.no_scrub_prefetch 0
vfs.zfs.mg_alloc_failures 12
vfs.zfs.write_to_degraded 0
vfs.zfs.check_hostid 1
vfs.zfs.recover 0
vfs.zfs.deadman_synctime 1000
vfs.zfs.deadman_enabled 1
vfs.zfs.txg.synctime_ms 1000
vfs.zfs.txg.timeout 5
vfs.zfs.vdev.cache.max 16384
vfs.zfs.vdev.cache.size 0
vfs.zfs.vdev.cache.bshift 16
vfs.zfs.vdev.trim_on_init 1
vfs.zfs.vdev.max_pending 10
vfs.zfs.vdev.min_pending 4
vfs.zfs.vdev.time_shift 29
vfs.zfs.vdev.ramp_rate 2
vfs.zfs.vdev.aggregation_limit 131072
vfs.zfs.vdev.read_gap_limit 32768
vfs.zfs.vdev.write_gap_limit 4096
vfs.zfs.vdev.bio_flush_disable 0
vfs.zfs.vdev.bio_delete_disable 0
vfs.zfs.vdev.trim_max_bytes 2147483648
vfs.zfs.vdev.trim_max_pending 64
vfs.zfs.zil_replay_disable 0
vfs.zfs.cache_flush_disable 0
vfs.zfs.zio.use_uma 0
vfs.zfs.sync_pass_deferred_free 2
vfs.zfs.sync_pass_dont_compress 5
vfs.zfs.sync_pass_rewrite 2
vfs.zfs.snapshot_list_prefetch 0
vfs.zfs.super_owner 0
vfs.zfs.debug 0
vfs.zfs.version.ioctl 3
vfs.zfs.version.acl 1
vfs.zfs.version.spa 5000
vfs.zfs.version.zpl 5
vfs.zfs.trim.enabled 0
vfs.zfs.trim.txg_delay 32
vfs.zfs.trim.timeout 30
vfs.zfs.trim.max_interval 1
------------------------------------------------------------------------
-----
Please tell me if you need anything else to diagnose the problem.
Regards,
--
Yoshiaki Kasahara
Research Institute for Information Technology, Kyushu University
kasahara at nc.kyushu-u.ac.jp
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