On Fri, Apr 13, 2007 at 10:15:05AM +0200, Laurent CARON wrote: > Neil Brown a écrit : > > On Thursday March 1, jpiszcz@xxxxxxxxxxxxxxx wrote: > >> You can only grow a RAID5 array in Linux as of 2.6.20 AFAIK. > > > > There are two dimensions for growth. > > You can increase the amount of each device that is used, or you can > > increase the number of devices. > > > > You are correct that increasing the number of devices only works for > > RAID5 (and RAID1, but you don't get extra space) in 2.6.20 (RAID6 > > coming in 2.6.21). > > > > However this question is about growing an array the first way: > > increasing the amount of space used on each devices, and that is > > supported for RAID1/4/5/6. > > > > And Laurent: > > 1/ Yes, it is that easy > > 2/ I doubt a nearly-full ext3 array increases the risk > > 3/ The effect of adding a bitmap is that if you suffer a crash while > > the array is degraded, it will resync faster so you have less > > exposure to multiple failure. > > I just finished changing disks, growing the array, and then the filesystem. > > It worked flawlessy. > > Just a little notice: I had to unmount my ext3 filesystem to be able to > resize it. (Took ~8 hours to fsck + resize the 15 disks array from 6 to > 9TB on a dual Xeon with 4GB RAM). FWIW: I changed a 6 x 400G system to 500G disks and grew the raid5 array. It worked fine save for these warnings: Apr 8 16:54:33 sylla mdadm: RebuildStarted event detected on md device /dev/md1 Apr 8 16:54:33 sylla mdadm: Rebuild20 event detected on md device /dev/md1 Apr 8 16:54:33 sylla mdadm: Rebuild40 event detected on md device /dev/md1 Apr 8 16:54:33 sylla mdadm: Rebuild60 event detected on md device /dev/md1 Apr 8 16:54:33 sylla mdadm: Rebuild80 event detected on md device /dev/md1 Apr 8 16:54:33 sylla kernel: md1: invalid bitmap page request: 187 (> 186) Apr 8 16:54:33 sylla kernel: md1: invalid bitmap page request: 187 (> 186) etc... So after rebooting I removed the bitmap and recreated it. Online resizing of the 2.0T xfs to 2.4T only took a few _seconds_. A similar operation on a 4 x 250G raid5 system upgraded to 400G disks with reiser3 also took a few seconds of _online_ time. Kernel 2.6.20.6 - 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
