raid-5 to raid-10 conversion for PERC-6i?

J. Epperson Dell at epperson.homelinux.net
Mon Feb 15 20:46:36 CST 2010


On Mon, February 15, 2010 20:39, Stroller wrote:
>
> On 15 Feb 2010, at 20:02, Alexander Dupuy wrote:
>> ...
>> The only approach that I can see might be to remove a drive from the
>> RAID-5 (making it into a RAID-0), then using the removed drive plus
>> the new one to create two RAID-1s in degraded state (is this even
>> possible?) ... Neither approach seems ideal - a disk failure during
>> the conversion would be fatal
>
> Suspect this migration is in no way supported, for the very reason you
> mention (disk failure). It sounds awfully messy.
>
> The solution that springs to mind is to buy a couple of large external
> hard-drives (or large SATA hard-drives in cheap external USB
> enclosures), boot to a Live CD (System Rescue CD, Knoppix) and clone
> the disk off onto them (e.g. using dd if=/dev/sda of=/mnt/usbdrive/
> system.img). Reconfigure the array, then clone back onto the new
> "virtual disk".
>

For cloning, can also use g4l w/lzop compression and write to local _or_
ftp server remote space.  Not bad on gig ethernet. Or do the live CD thing
and NFS mount space from elsewhere, piping the dd through lzop to
compress/uncompress.  If you binary zero free space first (dd if=/dev/zero
of=bigfile;rm bigfile) and depending how much free space there is,
compression can be a win against uncompressed write speed.  YMMV.



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