On Sat, 26 Jun 2010 15:12:35 +0200 Piergiorgio Sartor <piergiorgio.sartor@xxxxxxxx> wrote: > Hi, > > > Assuming the code doesn't have any bugs, the reshape will stop, then > > immediately restart picking up where it left off. > > thanks, that's what I wanted to know. > > > You will of course end up with a degraded array > > Yes, that was clear. > > > It might be nice in these circumstances to abort the reshape and revert back > > the the previous number of devices - particularly if it was the new device > > that failed. However that currently isn't supported. > > Well, probably as an option, it could be interesting. > > Actually, I would be still interested, we already > discussed the topic, on a RAID-5/6 with HDDs of > different size. > This would simplify many things... > > > > 1) > > > mdadm --grow ... > > > mdadm --wait > > > pvresize > > > > Yes. > > > > > > > > 2) > > > mdadm --grow > > > pvresize > > > > No. > > Until the reshape has completed, the extra space is not available. > > There seem to be an issue, here, maybe. > > Using the command line: > > mdadm --grow /dev/md/vol02 --bitmap=none; mdadm --grow /dev/md/vol02 -n 9 --backup-file=/var/tmp/md125.backup; mdadm --wait /dev/md/vol02; mdadm --grow /dev/md/vol02 --bitmap=internal --bitmap-chunk=128 > > Note that /dev/md/vol02 is the usual link to /dev/md125, > which should be the same for this scope, I guess. > > I got (in two independent tests): > > mdadm: Need to backup 2688K of critical section.. > mdadm: failed to set internal bitmap. > > Re-issuing: > > mdadm --wait /dev/md/vol02; mdadm --grow /dev/md/vol02 --bitmap=internal --bitmap-chunk=128 > > Does wait. > > Could it be the devices (being USB) are so slow > that some race condition is uncovered and the > immediate "--wait" after the "--grow" does not work? > Yes, there is a race here. The reshape doesn't quite start instantly and so --wait doesn't notice. I've added a note to my todo-list to look into this. For now, a 'sleep 1' between the --grow and the --wait should be enough. Thanks, NeilBrown -- 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
