On Tue, Sep 04, 2012 at 04:33:42PM +0100, Robin Hill wrote: > On Tue Sep 04, 2012 at 02:26:24PM +0200, Mikael Abrahamsson wrote: >> On Tue, 4 Sep 2012, David Brown wrote: >> >>> The "raid1" copy you mention will one day be possible with "hot replace" >>> <http://neil.brown.name/blog/20110216044002#2> >>> >>> I don't know how far along this idea is at the moment. >> >> https://lwn.net/Articles/465048/ >> >> "hot-replace support for RAID4/5/6: >> >> In order to activate hot-replace you need to mark the device as >> 'replaceable'. This happens automatically when a write error is recorded >> in a bad-block log (if you happen to have one). >> >> It can be achieved manually by >> echo replaceable > /sys/block/mdXX/md/dev-YYY/state >> >> This makes YYY, in XX, replaceable." >> >> I don't know if it actually made it into 3.2, I believe I saw somewhere >> that it was available for 3.3, but Neil Brown should know more. > > I'm currently upgrading my RAID-6 arrays via hot-replacement. The > process I followed (to replace device YYY in array mdXX) is: > - add the new disk to the array as a spare > - echo want_replacement > /sys/block/mdXX/md/dev-YYY/state > > That kicks off the recovery (a straight disk-to-disk copy from YYY to > the new disk). After the rebuild is complete, YYY gets failed in the > array, so can be safely removed: > - mdadm -r /dev/mdXX /dev/mdYYY > > That's worked fine so far, and looks to run at the single disk write > speed. There were no errors on the old disks though, so I've not seen > how that gets handled (it _should_ just do a parity-based recovery from > the remaining disks and continue). Thanks all, this is exactly what I was looking for! Cheers, Chris -- 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
