On Wed, 12 Oct 2011 10:25:16 +0100 Michael Busby <michael.a.busby@xxxxxxxxx> wrote: > Thanks, can i just double check the command with you > > mdadm --create /dev/md0 --chunk=512 --metadata=1.0 --assume-clean > --level=5 --raid-devices=4 /dev/sde /dev/sdc /dev/sdd /dev/sdb > Correct. Of course you have to mdadm --stop /dev/md0 first, but you knew that. NeilBrown > > On 12 October 2011 05:10, NeilBrown <neilb@xxxxxxx> wrote: > > On Mon, 10 Oct 2011 22:47:58 +0100 Michael Busby <michael.a.busby@xxxxxxxxx> > > wrote: > > > >> I have a quick question i remember reading somewhere about not using > >> metadata version 0.9 with drives larger than 2tb, > >> > at the moment i have the following > >> > > >> > root@BlueBolt:~# cat /proc/mdstat > >> > Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] > >> > md0 : active raid5 sdd[2] sde[0] sdb[3] sdc[1] > >> > 5860543488 blocks level 5, 512k chunk, algorithm 2 [4/4] [UUUU] > >> > bitmap: 2/15 pages [8KB], 65536KB chunk > >> > unused devices: <none> > >> > root@BlueBolt:~# mdadm --detail /dev/md0 > >> > /dev/md0: > >> > Version : 0.90 > >> > Creation Time : Mon Jul 4 15:08:38 2011 > >> > Raid Level : raid5 > >> > Array Size : 5860543488 (5589.05 GiB 6001.20 GB) > >> > Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB) > >> > Raid Devices : 4 > >> > Total Devices : 4 > >> > Preferred Minor : 0 > >> > Persistence : Superblock is persistent > >> > Intent Bitmap : Internal > >> > Update Time : Mon Oct 10 22:44:11 2011 > >> > State : active > >> > Active Devices : 4 > >> > Working Devices : 4 > >> > Failed Devices : 0 > >> > Spare Devices : 0 > >> > Layout : left-symmetric > >> > Chunk Size : 512K > >> > UUID : ddab6c38:dee3ead0:95ba4558:1c9a49ed (local to host BlueBolt) > >> > Events : 0.2836102 > >> > Number Major Minor RaidDevice State > >> > 0 8 64 0 active sync /dev/sde > >> > 1 8 32 1 active sync /dev/sdc > >> > 2 8 48 2 active sync /dev/sdd > >> > 3 8 16 3 active sync /dev/sdb > >> > which as you can see if using 0.90, i am looking at replacing all the 2tb drives with 3tb versions, would i need to update the metadata version? if so how can i go about this? > > > > With a really recent kernel (3.1) and recent mdadm (also not released yet), > > 0.90 can go up to 4TB (it has 32 bits to count kilobytes with). > > > > Alternately you need to convert to 1.0 metadata. > > > > Currently the only way to do this is to 'create' the array again. > > Be sure to specified the same chunk size, the right metadata, the name level > > and number of disks, and the correct disks in the correct order. > > An use "--assume-clean". Then check your data is still consistent. > > With --assume-clean and a read-only mount, no data will actually be changed, > > only metadata. > > > > NeilBrown > > > >
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