Date: Tue, 26 Apr 2016 18:50:09 +0200 From: Miroslav Lachman <000.fbsd@quip.cz> To: Jeremy Faulkner <gldisater@gmail.com>, freebsd-fs@freebsd.org Subject: Re: How to speed up slow zpool scrub? Message-ID: <571F9C41.9020406@quip.cz> In-Reply-To: <571F9064.2010602@gmail.com> References: <571F62AD.6080005@quip.cz> <571F687D.8040103@internetx.com> <571F6EA4.90800@quip.cz> <571F82B5.3010807@gmail.com> <571F845C.5060902@quip.cz> <571F9064.2010602@gmail.com>
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Jeremy Faulkner wrote on 04/26/2016 17:59:
> Check the drive health with smartctl (part of sysutils/smartmontools).
> Are the drives desktop drives or nas drives? In gstat is one drive
> busier than the rest? If so, replace that drive.
# iostat -x -w 15 ada0 ada1 ada2 ada3
..
..
extended device statistics
device r/s w/s kr/s kw/s qlen svc_t %b
ada0 215.3 15.7 5045.6 492.5 2 8.1 64
ada1 220.1 15.6 5063.2 492.0 2 8.0 65
ada2 221.7 15.1 4917.9 479.2 1 8.1 66
ada3 224.1 15.2 4910.4 482.9 0 8.1 67
extended device statistics
device r/s w/s kr/s kw/s qlen svc_t %b
ada0 220.8 13.5 4497.7 624.8 0 6.7 61
ada1 224.7 13.1 4503.6 625.3 0 6.8 61
ada2 206.5 12.3 4287.3 599.7 0 6.2 60
ada3 208.3 12.8 4289.2 619.2 0 6.4 60
extended device statistics
device r/s w/s kr/s kw/s qlen svc_t %b
ada0 236.5 8.1 5219.4 392.2 1 6.4 61
ada1 231.5 8.1 5199.4 390.6 1 6.4 61
ada2 242.5 7.5 5075.7 379.7 2 5.4 58
ada3 240.3 7.7 5048.2 383.7 2 5.9 58
Drives are 60% busy when scrubbing and deleting old files are both
running so I think there is still something to tune.
Miroslav Lachman
# ~/bin/arc_summary.sh
System Memory:
Physical RAM: 4962 MB
Free Memory : 108 MB
ARC Size:
Current Size: 3373 MB (arcsize)
Target Size (Adaptive): 3372 MB (c)
Min Size (Hard Limit): 512 MB (zfs_arc_min)
Max Size (Hard Limit): 3584 MB (zfs_arc_max)
ARC Size Breakdown:
Most Recently Used Cache Size: 93% 3161 MB (p)
Most Frequently Used Cache Size: 6% 210 MB (c-p)
ARC Efficency:
Cache Access Total: 2605059457
Cache Hit Ratio: 79% 2072273907 [Defined State
for buffer]
Cache Miss Ratio: 20% 532785550 [Undefined
State for Buffer]
REAL Hit Ratio: 72% 1898031795 [MRU/MFU Hits Only]
Data Demand Efficiency: 91%
Data Prefetch Efficiency: 1%
CACHE HITS BY CACHE LIST:
Anon: 7% 158713873
[ New Customer, First Cache Hit ]
Most Recently Used: 55% 1154441329 (mru)
[ Return Customer ]
Most Frequently Used: 35% 743590466 (mfu)
[ Frequent Customer ]
Most Recently Used Ghost: 0% 11032454 (mru_ghost)
[ Return Customer Evicted, Now Back ]
Most Frequently Used Ghost: 0% 4495785 (mfu_ghost)
[ Frequent Customer Evicted, Now Back ]
CACHE HITS BY DATA TYPE:
Demand Data: 10% 226614173
Prefetch Data: 0% 519707
Demand Metadata: 80% 1669964501
Prefetch Metadata: 8% 175175526
CACHE MISSES BY DATA TYPE:
Demand Data: 3% 20563634
Prefetch Data: 9% 50227920
Demand Metadata: 79% 422689982
Prefetch Metadata: 7% 39304014
---------------------------------------------
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