mpyusko
Dabbler
- Joined
- Jul 5, 2019
- Messages
- 49
I mentioned this as a side note in another thread, but it really needs it's own discussion. Adding in the notes from the previous discussion.
I have an old FreeNAS 9.10 box maxed out at 8GB RAM running with a 240 GB SSD for the L2ARC with just shy of 17 TB written to it.....
What is strange is the ARC/L2ARC sizes reported there vs my 11.2 box.
(How can 8GB RAM equal 163 GB ARC and a 240 GB SSD equal a 443 GB L2ARC???)
We weighed the options, and ultimately, it came down to being able to compensate to the limitation of the integrated SATA-II controller. Although the array is built out of 4 WD Golds (RAID10), the ammount of I/O trraffic beween the steady flow of email and database transactions made it crawl. The L2ARC helps alleviate that.
I have an old FreeNAS 9.10 box maxed out at 8GB RAM running with a 240 GB SSD for the L2ARC with just shy of 17 TB written to it.....
What is strange is the ARC/L2ARC sizes reported there vs my 11.2 box.
(How can 8GB RAM equal 163 GB ARC and a 240 GB SSD equal a 443 GB L2ARC???)
We weighed the options, and ultimately, it came down to being able to compensate to the limitation of the integrated SATA-II controller. Although the array is built out of 4 WD Golds (RAID10), the ammount of I/O trraffic beween the steady flow of email and database transactions made it crawl. The L2ARC helps alleviate that.
Code:
[root@fn1] ~# arc_summary.py
System Memory:
1.59% 126.18 MiB Active, 10.05% 797.65 MiB Inact
75.83% 5.88 GiB Wired, 0.20% 16.10 MiB Cache
12.33% 978.83 MiB Free, 0.00% 0 Bytes Gap
Real Installed: 8.00 GiB
Real Available: 99.61% 7.97 GiB
Real Managed: 97.28% 7.75 GiB
Logical Total: 8.00 GiB
Logical Used: 78.12% 6.25 GiB
Logical Free: 21.88% 1.75 GiB
Kernel Memory: 254.07 MiB
Data: 89.11% 226.41 MiB
Text: 10.89% 27.67 MiB
Kernel Memory Map: 7.75 GiB
Size: 27.90% 2.16 GiB
Free: 72.10% 5.59 GiB
Page: 1
------------------------------------------------------------------------
ARC Summary: (HEALTHY)
Storage pool Version: 5000
Filesystem Version: 5
Memory Throttle Count: 0
ARC Misc:
Deleted: 2.19b
Mutex Misses: 2.24b
Evict Skips: 2.24b
ARC Size: 2427.36% 163.88 GiB
Target Size: (Adaptive) 100.00% 6.75 GiB
Min Size (Hard Limit): 12.50% 864.18 MiB
Max Size (High Water): 8:1 6.75 GiB
ARC Size Breakdown:
Recently Used Cache Size: 2.87% 4.71 GiB
Frequently Used Cache Size: 97.13% 159.17 GiB
ARC Hash Breakdown:
Elements Max: 40.48m
Elements Current: 36.82% 14.90m
Collisions: 9.39b
Chain Max: 70
Chains: 1.05m
Page: 2
------------------------------------------------------------------------
ARC Total accesses: 4.40b
Cache Hit Ratio: 20.71% 911.03m
Cache Miss Ratio: 79.29% 3.49b
Actual Hit Ratio: 17.89% 786.84m
Data Demand Efficiency: 18.04% 2.92b
Data Prefetch Efficiency: 30.50% 387.71m
CACHE HITS BY CACHE LIST:
Most Recently Used: 73.12% 666.15m
Most Frequently Used: 13.25% 120.69m
Most Recently Used Ghost: 121.64% 1.11b
Most Frequently Used Ghost: 46.88% 427.08m
CACHE HITS BY DATA TYPE:
Demand Data: 57.74% 526.06m
Prefetch Data: 12.98% 118.25m
Demand Metadata: 23.73% 216.20m
Prefetch Metadata: 5.55% 50.52m
CACHE MISSES BY DATA TYPE:
Demand Data: 68.56% 2.39b
Prefetch Data: 7.73% 269.46m
Demand Metadata: 19.52% 680.71m
Prefetch Metadata: 4.19% 146.01m
Page: 3
------------------------------------------------------------------------
L2 ARC Summary: (DEGRADED)
Passed Headroom: 23.59m
Tried Lock Failures: 9.61m
IO In Progress: 9.16m
Low Memory Aborts: 249
Free on Write: 9.74m
Writes While Full: 499.02k
R/W Clashes: 0
Bad Checksums: 762.89m
IO Errors: 0
SPA Mismatch: 159.11m
L2 ARC Size: (Adaptive) 443.70 GiB
Header Size: 0.27% 1.19 GiB
L2 ARC Evicts:
Lock Retries: 6.18k
Upon Reading: 0
L2 ARC Breakdown: 3.49b
Hit Ratio: 37.55% 1.31b
Miss Ratio: 62.45% 2.18b
Feeds: 47.70m
L2 ARC Buffer:
Bytes Scanned: 1.08 PiB
Buffer Iterations: 47.70m
List Iterations: 190.81m
NULL List Iterations: 130.01m
L2 ARC Writes:
Writes Sent: 100.00% 15.41m
Page: 4
------------------------------------------------------------------------
DMU Prefetch Efficiency: 17.78b
Hit Ratio: 2.75% 489.48m
Miss Ratio: 97.25% 17.29b
Page: 5
------------------------------------------------------------------------
Page: 6
------------------------------------------------------------------------
ZFS Tunable (sysctl):
kern.maxusers 845
vm.kmem_size 8323047424
vm.kmem_size_scale 1
vm.kmem_size_min 0
vm.kmem_size_max 1319413950874
vfs.zfs.vol.unmap_enabled 1
vfs.zfs.vol.mode 2
vfs.zfs.sync_pass_rewrite 2
vfs.zfs.sync_pass_dont_compress 5
vfs.zfs.sync_pass_deferred_free 2
vfs.zfs.zio.dva_throttle_enabled 1
vfs.zfs.zio.exclude_metadata 0
vfs.zfs.zio.use_uma 1
vfs.zfs.zil_slog_limit 786432
vfs.zfs.cache_flush_disable 0
vfs.zfs.zil_replay_disable 0
vfs.zfs.version.zpl 5
vfs.zfs.version.spa 5000
vfs.zfs.version.acl 1
vfs.zfs.version.ioctl 7
vfs.zfs.debug 0
vfs.zfs.super_owner 0
vfs.zfs.min_auto_ashift 12
vfs.zfs.max_auto_ashift 13
vfs.zfs.vdev.queue_depth_pct 1000
vfs.zfs.vdev.write_gap_limit 4096
vfs.zfs.vdev.read_gap_limit 32768
vfs.zfs.vdev.aggregation_limit 131072
vfs.zfs.vdev.trim_max_active 64
vfs.zfs.vdev.trim_min_active 1
vfs.zfs.vdev.scrub_max_active 2
vfs.zfs.vdev.scrub_min_active 1
vfs.zfs.vdev.async_write_max_active 10
vfs.zfs.vdev.async_write_min_active 1
vfs.zfs.vdev.async_read_max_active 3
vfs.zfs.vdev.async_read_min_active 1
vfs.zfs.vdev.sync_write_max_active 10
vfs.zfs.vdev.sync_write_min_active 10
vfs.zfs.vdev.sync_read_max_active 10
vfs.zfs.vdev.sync_read_min_active 10
vfs.zfs.vdev.max_active 1000
vfs.zfs.vdev.async_write_active_max_dirty_percent60
vfs.zfs.vdev.async_write_active_min_dirty_percent30
vfs.zfs.vdev.mirror.non_rotating_seek_inc1
vfs.zfs.vdev.mirror.non_rotating_inc 0
vfs.zfs.vdev.mirror.rotating_seek_offset1048576
vfs.zfs.vdev.mirror.rotating_seek_inc 5
vfs.zfs.vdev.mirror.rotating_inc 0
vfs.zfs.vdev.trim_on_init 1
vfs.zfs.vdev.larger_ashift_minimal 0
vfs.zfs.vdev.bio_delete_disable 0
vfs.zfs.vdev.bio_flush_disable 0
vfs.zfs.vdev.cache.bshift 16
vfs.zfs.vdev.cache.size 0
vfs.zfs.vdev.cache.max 16384
vfs.zfs.vdev.metaslabs_per_vdev 200
vfs.zfs.vdev.trim_max_pending 10000
vfs.zfs.txg.timeout 5
vfs.zfs.trim.enabled 1
vfs.zfs.trim.max_interval 1
vfs.zfs.trim.timeout 30
vfs.zfs.trim.txg_delay 32
vfs.zfs.space_map_blksz 4096
vfs.zfs.spa_min_slop 134217728
vfs.zfs.spa_slop_shift 5
vfs.zfs.spa_asize_inflation 24
vfs.zfs.deadman_enabled 1
vfs.zfs.deadman_checktime_ms 5000
vfs.zfs.deadman_synctime_ms 1000000
vfs.zfs.debug_flags 0
vfs.zfs.recover 0
vfs.zfs.spa_load_verify_data 1
vfs.zfs.spa_load_verify_metadata 1
vfs.zfs.spa_load_verify_maxinflight 10000
vfs.zfs.ccw_retry_interval 300
vfs.zfs.check_hostid 1
vfs.zfs.mg_fragmentation_threshold 85
vfs.zfs.mg_noalloc_threshold 0
vfs.zfs.condense_pct 200
vfs.zfs.metaslab.bias_enabled 1
vfs.zfs.metaslab.lba_weighting_enabled 1
vfs.zfs.metaslab.fragmentation_factor_enabled1
vfs.zfs.metaslab.preload_enabled 1
vfs.zfs.metaslab.preload_limit 3
vfs.zfs.metaslab.unload_delay 8
vfs.zfs.metaslab.load_pct 50
vfs.zfs.metaslab.min_alloc_size 33554432
vfs.zfs.metaslab.df_free_pct 4
vfs.zfs.metaslab.df_alloc_threshold 131072
vfs.zfs.metaslab.debug_unload 0
vfs.zfs.metaslab.debug_load 0
vfs.zfs.metaslab.fragmentation_threshold70
vfs.zfs.metaslab.gang_bang 16777217
vfs.zfs.free_bpobj_enabled 1
vfs.zfs.free_max_blocks 18446744073709551615
vfs.zfs.no_scrub_prefetch 0
vfs.zfs.no_scrub_io 0
vfs.zfs.resilver_min_time_ms 3000
vfs.zfs.free_min_time_ms 1000
vfs.zfs.scan_min_time_ms 1000
vfs.zfs.scan_idle 50
vfs.zfs.scrub_delay 4
vfs.zfs.resilver_delay 2
vfs.zfs.top_maxinflight 32
vfs.zfs.delay_scale 500000
vfs.zfs.delay_min_dirty_percent 60
vfs.zfs.dirty_data_sync 67108864
vfs.zfs.dirty_data_max_percent 10
vfs.zfs.dirty_data_max_max 4294967296
vfs.zfs.dirty_data_max 855611392
vfs.zfs.max_recordsize 1048576
vfs.zfs.zfetch.array_rd_sz 1048576
vfs.zfs.zfetch.max_distance 8388608
vfs.zfs.zfetch.min_sec_reap 2
vfs.zfs.zfetch.max_streams 8
vfs.zfs.prefetch_disable 0
vfs.zfs.send_holes_without_birth_time 1
vfs.zfs.mdcomp_disable 0
vfs.zfs.nopwrite_enabled 1
vfs.zfs.dedup.prefetch 1
vfs.zfs.l2c_only_size 0
vfs.zfs.mfu_ghost_data_esize 3325952
vfs.zfs.mfu_ghost_metadata_esize 111502336
vfs.zfs.mfu_ghost_size 114828288
vfs.zfs.mfu_data_esize 5120
vfs.zfs.mfu_metadata_esize 0
vfs.zfs.mfu_size 95766528
vfs.zfs.mru_ghost_data_esize 2437057024
vfs.zfs.mru_ghost_metadata_esize 4690575872
vfs.zfs.mru_ghost_size 7127632896
vfs.zfs.mru_data_esize 0
vfs.zfs.mru_metadata_esize 0
vfs.zfs.mru_size 116867072
vfs.zfs.anon_data_esize 0
vfs.zfs.anon_metadata_esize 0
vfs.zfs.anon_size 7898624
vfs.zfs.l2arc_norw 1
vfs.zfs.l2arc_feed_again 1
vfs.zfs.l2arc_noprefetch 1
vfs.zfs.l2arc_feed_min_ms 200
vfs.zfs.l2arc_feed_secs 1
vfs.zfs.l2arc_headroom 2
vfs.zfs.l2arc_write_boost 8388608
vfs.zfs.l2arc_write_max 8388608
vfs.zfs.arc_meta_limit 1812326400
vfs.zfs.arc_free_target 14135
vfs.zfs.compressed_arc_enabled 1
vfs.zfs.arc_shrink_shift 7
vfs.zfs.arc_average_blocksize 8192
vfs.zfs.arc_min 906163200
vfs.zfs.arc_max 7249305600
Page: 7
------------------------------------------------------------------------
[root@fn1] ~#This box mostly handles emails and databases.
