> Check the I/O performance on the box. I think the "speed" indicator comes
> out of calculations to determine how fast a failing drive would be
> rebuilt, were you doing a rebuild instead of a check. I like using the
> "dstat" tool to get that info at-a-glance
> (http://dag.wieers.com/home-made/dstat/).
Thank you, you're quite right! Running dtst during the check shows
--dsk/sda-----dsk/sdb-----dsk/sdc-----dsk/sdd-----dsk/sde-----dsk/sdf----dsk/total-
_read _writ:_read _writ:_read _writ:_read _writ:_read _writ:_read _writ:_read
_writ
2954k 37k:2952k 36k:2954k 37k:2952k 35k:2955k 37k:2952k 35k: 17M
217k
62M 0 : 62M 0 : 62M 0 : 62M 0 : 61M 0 : 62M 0 : 370M
0
62M 0 : 62M 0 : 62M 0 : 62M 0 : 62M 0 : 62M 0 : 372M
0
62M 8192B: 62M 76k: 62M 76k: 62M 36k: 62M 36k: 62M 8192B: 373M
240k
47M 8192B: 47M 8192B: 47M 8192B: 47M 8192B: 47M 8192B: 47M 8192B: 283M
48k
59M 16k: 59M 16k: 59M 16k: 59M 100k: 59M 100k: 59M 16k: 353M
264k
63M 0 : 63M 0 : 63M 0 : 63M 0 : 63M 0 : 63M 0 : 378M
0
58M 0 : 58M 0 : 58M 0 : 58M 0 : 58M 0 : 58M 0 : 348M
0
57M 0 : 58M 0 : 58M 0 : 57M 0 : 58M 0 : 58M 0 : 345M
0
61M 0 : 61M 0 : 61M 0 : 61M 0 : 61M 0 : 61M 0 : 365M
0
61M 0 : 60M 0 : 60M 0 : 61M 0 : 60M 0 : 60M 0 : 363M
0
60M 16k: 60M 20k: 59M 20k: 59M 28k: 59M 28k: 60M 16k: 356M
128k
Whish is 60 MB/drive, exactly as expected.
On RAID-5, I could call it a "redundancy checking rate", but that doesn't
correspond to the RAID-1 numbers:
md0 : active raid1 sdf1[5] sde1[4] sdd1[3] sdc1[2] sdb1[1] sda1[0]
979840 blocks [6/6] [UUUUUU]
[==>..................] resync = 14.3% (140480/979840) finish=0.4min
speed=28096K/sec
Judging from dstat, that 28 MB/s figure is a per-drive. (And I wonder
why *that* is so low.)
But anyway, good work on RAID-5! Multi-way RAID-1 isn't economical on large
volumes of data, so it's hard to get very concerned about the speed. I *can*
get > 60 MB/s per drive on 3 parallel 2-way RAID-1 checks.
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