What's up with the swapping since 10/stable

Matthias Gamsjager mgamsjager at gmail.com
Sun Feb 2 17:01:11 UTC 2014


Hi,

My ZFS Nas box seems to use some swap since the upgrade to 10/stable. This
machine just runs couple of hours per week and with 9/stable I never
witnessed any swapping when serving media files.

First thinks that caught my eye was the difference between ARC and Wired.
At some point there is a 1+ GB difference while all this machine does is
serving single 10GB mkv via AFP.

Problem is that at some point the performance get's to a point that
streaming isn't possible.

This is after couple of video's watched and scrub 99% done.

No ZFS tuning in /boot/loader.conf

last pid:  2571;  load averages:  0.19,  0.20,  0.19              up
0+04:06:20  17:55:43

42 processes:  1 running, 41 sleeping

CPU:  0.0% user,  0.0% nice,  2.3% system,  0.0% interrupt, 97.7% idle

Mem: 32M Active, 14M Inact, 7563M Wired, 16M Cache, 273M Buf, 303M Free

ARC: 6065M Total, 2142M MFU, 3309M MRU, 50K Anon, 136M Header, 478M Other

Swap: 4096M Total, 66M Used, 4030M Free, 1% Inuse


System Information:


 Kernel Version:  1000702 (osreldate)

Hardware Platform:  amd64

Processor Architecture:  amd64


 ZFS Storage pool Version: 5000

ZFS Filesystem Version:  5


FreeBSD 10.0-STABLE #0 r261210: Mon Jan 27 15:19:13 CET 2014 matty

 5:57PM  up  4:08, 2 users, load averages: 0.31, 0.23, 0.21


------------------------------------------------------------------------


System Memory:


 0.41% 32.43 MiB Active, 0.18% 14.11 MiB Inact

95.39% 7.39 GiB Wired, 0.21% 16.37 MiB Cache

3.81% 301.97 MiB Free, 0.01% 784.00 KiB Gap


 Real Installed:  8.00 GiB

Real Available:  99.50% 7.96 GiB

Real Managed:  97.28% 7.74 GiB


 Logical Total:  8.00 GiB

Logical Used:  95.94% 7.68 GiB

Logical Free:  4.06% 332.45 MiB


Kernel Memory:   196.21 MiB

Data:  79.49% 155.96 MiB

Text:  20.51% 40.25 MiB


Kernel Memory Map:  7.74 GiB

Size:  71.72% 5.55 GiB

Free:  28.28% 2.19 GiB


------------------------------------------------------------------------


ARC Summary: (HEALTHY)

Memory Throttle Count:  0


ARC Misc:

Deleted:  34.10k

Recycle Misses:  102.86k

Mutex Misses:  10

Evict Skips:  989.63k


ARC Size:  87.94% 5.93 GiB

Target Size: (Adaptive) 90.63% 6.11 GiB

Min Size (Hard Limit): 12.50% 863.10 MiB

Max Size (High Water): 8:1 6.74 GiB


ARC Size Breakdown:

Recently Used Cache Size: 65.86% 4.02 GiB

Frequently Used Cache Size: 34.14% 2.09 GiB


ARC Hash Breakdown:

Elements Max:  594.22k

Elements Current: 100.00% 594.21k

Collisions:  609.54k

Chain Max:  15

Chains:   122.92k


------------------------------------------------------------------------


ARC Efficiency:   4.19m

Cache Hit Ratio: 83.08% 3.48m

Cache Miss Ratio: 16.92% 708.94k

Actual Hit Ratio: 73.81% 3.09m


 Data Demand Efficiency: 79.24% 456.96k

Data Prefetch Efficiency: 2.94% 90.16k


 CACHE HITS BY CACHE LIST:

  Anonymously Used: 8.80% 306.18k

  Most Recently Used: 23.42% 815.06k

  Most Frequently Used: 65.43% 2.28m

  Most Recently Used Ghost: 0.41% 14.36k

  Most Frequently Used Ghost: 1.94% 67.65k


 CACHE HITS BY DATA TYPE:

  Demand Data:  10.40% 362.08k

  Prefetch Data: 0.08% 2.65k

  Demand Metadata: 76.84% 2.67m

  Prefetch Metadata: 12.68% 441.47k


 CACHE MISSES BY DATA TYPE:

  Demand Data:  13.38% 94.88k

  Prefetch Data: 12.34% 87.51k

  Demand Metadata: 34.54% 244.88k

  Prefetch Metadata: 39.73% 281.67k


------------------------------------------------------------------------


L2ARC is disabled


------------------------------------------------------------------------


File-Level Prefetch: (HEALTHY)


DMU Efficiency:   9.57m

Hit Ratio:  73.77% 7.06m

Miss Ratio:  26.23% 2.51m


 Colinear:  2.51m

  Hit Ratio:  0.06% 1.54k

  Miss Ratio:  99.94% 2.51m


 Stride:   6.92m

  Hit Ratio:  99.99% 6.92m

  Miss Ratio:  0.01% 594


DMU Misc:

Reclaim:  2.51m

  Successes:  0.85% 21.28k

  Failures:  99.15% 2.49m


 Streams:  137.84k

  +Resets:  0.06% 79

  -Resets:  99.94% 137.76k

  Bogus:  0


------------------------------------------------------------------------


VDEV cache is disabled


------------------------------------------------------------------------


ZFS Tunables (sysctl):

kern.maxusers                           845

vm.kmem_size                            8313913344

vm.kmem_size_scale                      1

vm.kmem_size_min                        0

vm.kmem_size_max                        1319413950874

vfs.zfs.arc_max                         7240171520

vfs.zfs.arc_min                         905021440

vfs.zfs.arc_meta_used                   2166001368

vfs.zfs.arc_meta_limit                  1810042880

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                       51200

vfs.zfs.anon_metadata_lsize             0

vfs.zfs.anon_data_lsize                 0

vfs.zfs.mru_size                        3476498432

vfs.zfs.mru_metadata_lsize              1319031808

vfs.zfs.mru_data_lsize                  2150589440

vfs.zfs.mru_ghost_size                  361860096

vfs.zfs.mru_ghost_metadata_lsize        210866688

vfs.zfs.mru_ghost_data_lsize            150993408

vfs.zfs.mfu_size                        2246172672

vfs.zfs.mfu_metadata_lsize              32768

vfs.zfs.mfu_data_lsize                  2050486272

vfs.zfs.mfu_ghost_size                  6198800896

vfs.zfs.mfu_ghost_metadata_lsize        2818404864

vfs.zfs.mfu_ghost_data_lsize            3380396032

vfs.zfs.l2c_only_size                   0

vfs.zfs.dedup.prefetch                  1

vfs.zfs.nopwrite_enabled                1

vfs.zfs.mdcomp_disable                  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.metaslab.gang_bang              131073

vfs.zfs.metaslab.debug                  0

vfs.zfs.metaslab.df_alloc_threshold     131072

vfs.zfs.metaslab.df_free_pct            4

vfs.zfs.metaslab.min_alloc_size         10485760

vfs.zfs.metaslab.prefetch_limit         3

vfs.zfs.metaslab.smo_bonus_pct          150

vfs.zfs.mg_alloc_failures               8

vfs.zfs.write_to_degraded               0

vfs.zfs.check_hostid                    1

vfs.zfs.recover                         0

vfs.zfs.deadman_synctime_ms             1000000

vfs.zfs.deadman_checktime_ms            5000

vfs.zfs.deadman_enabled                 1

vfs.zfs.space_map_last_hope             0

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_active                 1000

vfs.zfs.vdev.sync_read_min_active       10

vfs.zfs.vdev.sync_read_max_active       10

vfs.zfs.vdev.sync_write_min_active      10

vfs.zfs.vdev.sync_write_max_active      10

vfs.zfs.vdev.async_read_min_active      1

vfs.zfs.vdev.async_read_max_active      3

vfs.zfs.vdev.async_write_min_active     1

vfs.zfs.vdev.async_write_max_active     10

vfs.zfs.vdev.scrub_min_active           1

vfs.zfs.vdev.scrub_max_active           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.max_auto_ashift                 13

vfs.zfs.zil_replay_disable              0

vfs.zfs.cache_flush_disable             0

vfs.zfs.zio.use_uma                     1

vfs.zfs.zio.exclude_metadata            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                    1

vfs.zfs.trim.txg_delay                  32

vfs.zfs.trim.timeout                    30

vfs.zfs.trim.max_interval               1


------------------------------------------------------------------------


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