On Tuesday August 7, saeed.bishara@xxxxxxxxx wrote: > On 8/7/07, Neil Brown <neilb@xxxxxxx> wrote: > > On Tuesday August 7, saeed.bishara@xxxxxxxxx wrote: > > > how can I create raid 5 array that preserves the contents of a given > > > disk (part of the array)? > > > I can do that in two steps, raid 5 on two disks then reshape it to be > > > real raid5, but is there a direct way to do it? > > > > What do you mean by "real raid 5". Two disks are just as much an > > array as 10. > I meant by real raid 5 to raid 5 over 3 drives or above. > > What do you mean by "direct". If I understand your requirements > in one mdadm command > > correctly, there are two obvious steps. > > 1/ make the data appear in a raid5 > > 2/ change the number of devices in the raid5. > > > > Are two steps too many? > in this case I two options: > 1. keep the filesystem unmounted tell step 1 in done -> the fs will > not be available for long time No, it shouldn't take a long time.... What exactly do you have, and what exactly do you want to achieve? If think you started of by saying you wanted to convert a raid1 to a raid5. Yes, that requires the filesystem to be unmounted, but only takes seconds to achieve: mdadm -S /dev/md0 mdadm -C /dev/md0 -l5 -n2 /dev/sda1 /dev/sdb1 mount /dev/md0 If you have a single-disk, you first might need to shrink the filesystem to make sure there is 128K free at the end of the device: umount /filesystem resize2fs /dev/sda1 whatever-number mdadm -C /dev/md0 -l5 -n1 /dev/sda1 missing mount /dev/md0 /filesystem # now add the drives and grow mdadm /dev/md0 --add /dev/sdb1 /dev/sdc1 # wait for recovery to finish mdadm --grow /dev/md0 --raid-disks=3 something like that.. 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
