> > I'm a but confused about the duration of a raid5 resync: > > > > - occasionally, my server with 4*750 gb sata raid5 crashed (because of > > problems with the power supply); after rebooting it took about 10 to 12 > > hours to resync the raid5 (guess it just re-created some parity > > information or however it works internally, but didn't have to copy > > any data) > > A resync reads all the data and checks the parity. If it find bad > parity (which is likely to be very rare) then it corrects it. > So resync should run at the full speed of the hardware, just reading. It will? Maybe I am just mis-remembering, but I thought I saw the same note in the log when the resync occurred (ckarray) as when a recovery was in progress: May 14 22:40:42 Backup kernel: [ 8083.747787] md: recovery of RAID array md0 May 14 22:40:42 Backup kernel: [ 8083.747789] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. May 14 22:40:42 Backup kernel: [ 8083.747791] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for recovery. May 14 22:40:42 Backup kernel: [ 8083.747797] md: using 128k window, over a total of 1465138432 blocks. Am I mis-remembering, or am I missing something here? Oh, while I am thinking of it, ckarray runs every month on the first of the month, but how can one trigger it manually? -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
