On 2013-04-11 02:10, James Harper wrote: [...]
with disks (and raid arrays) of that size, you also have to be concerned about data errors as well as disk failures - you're pretty much guaranteed to get some, either unrecoverable errors or, worse, silent corruption of the data.
Guaranteed over what time period? It's easy to fault your logic as I just did a full scan of my array and it came up clean. If you say you are "guaranteed to get some" over, say, a 10 year period, then I guess that's fair enough. But as you don't specify a timeframe I can't really contest the point. [...]
With a pair of 2TB Western Digital SATA drives in my server, both in RAID 1: | mattcen@adam:tmp$ zgrep -h 'mismatches found' /var/log/syslog* | sort -n | 2012-02-05T22:05:03.118792+11:00 adam mdadm[1545]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 10496 | 2012-03-04T17:00:12.084923+11:00 adam mdadm[1724]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 11008 | 2012-04-01T18:20:08.394369+10:00 adam mdadm[1724]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 10496 | 2012-05-06T16:42:59.386193+10:00 adam mdadm[1724]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 10240 | 2012-06-03T19:26:13.770869+10:00 adam mdadm[1559]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 10112 | 2012-07-01T17:32:36.678284+10:00 adam mdadm[2500]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 8960 | 2012-08-05T17:40:38.175882+10:00 adam mdadm[1859]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 8960 | 2012-09-04T05:52:52.107219+10:00 adam mdadm[1859]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 8832 | 2012-11-04T17:00:11.945288+11:00 adam mdadm[2475]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 1152 | 2012-12-02T20:34:26.204077+11:00 adam mdadm[2475]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 640 | 2013-01-06T19:51:39.551018+11:00 adam mdadm[2475]: RebuildFinished event detected on md device /dev/md/1, component device mismatches found: 640 With some of the systems we have at work, also in RAID 1: | mattcen@logos:tmp$ sudo zgrep -h 'mismatches found' /var/log/syslog* | sort -n | 2012-07-01T03:05:23.155717+10:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 1664 | 2012-07-02T15:39:28.372216+10:00 omega mdadm[4719]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 54528 | 2012-08-05T03:25:43.174057+10:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 1664 | 2012-08-06T19:11:30.325608+10:00 omega mdadm[4719]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 7552 | 2012-09-03T09:32:21.701674+10:00 omega mdadm[3691]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 7040 | 2012-09-15T22:29:27.704673+10:00 omega mdadm[3691]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 7040 | 2012-10-07T05:02:00.117419+11:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 512 | 2012-10-08T17:50:00.910978+11:00 omega mdadm[3691]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 6784 | 2012-11-04T03:40:25.763854+11:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 384 | 2012-11-05T20:41:37.945275+11:00 omega mdadm[3691]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 6528 | 2012-12-02T04:20:47.193559+11:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 2304 | 2012-12-03T23:18:57.661636+11:00 omega mdadm[3691]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 6400 | 2013-01-06T04:14:42.396266+11:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 2176 | 2013-02-03T05:00:35.431187+11:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 3328 | 2013-02-04T14:47:29.782264+11:00 omega mdadm[3300]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 3840 | 2013-03-03T04:34:35.005451+11:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 33152 | 2013-03-04T19:34:09.974437+11:00 omega mdadm[3300]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 5248 | 2013-04-07T03:55:32.146377+10:00 theta mdadm[1307]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 36992 | 2013-04-08T06:22:45.468885+10:00 omega mdadm[3300]: RebuildFinished event detected on md device /dev/md1, component device mismatches found: 72064 This is all on a monthly check schedule, so the unlisted months, everything came up clean. -- Regards, Matthew Cengia