Re: Raid over USB disks and eject

[Benjamin ESTRABAUD <be@mpstor.com>]

Hi!

You could setup a cron job that will pause the resync by writing to sysfs:

If your array if "md0":

echo "idle" > /sys/block/md0/md/sync_action

However, this is probably not necessary as the resynced stripes will be 
marked in the bitmap, meaning that if your rebuild fails, re-assembling 
the array should restart the resync from where it stopped.

Regards,
Ben.

On 12/11/12 12:44, Salatiel Filho wrote:
> Hi guys,  i have an external USB enclosure with 4 disks  in RAID5 mode
> using mdadm. I dont know exactly why but if i use this disks for
> massive I/O for lots of hours (over 12 hours), linux usually eject
> some or all disks (causing a faulty in the raid) and remaps them: sdb
> -> sdf , sdc -> sdg , sdd -> sdh , sde -> sdi
> Well , this was never exactly a problem because most of the time those
> disks are idle (just backup), but i had a real disk failure and i will
> replace the disk. But probably the rebuild process will take a lot
> more than 12 hours so the chances are that some disk will be ejected
> and i will be in a trouble situation where a raid5 rebuilding process
> will probably be stopped by an apparently failure. So my question is:
>
> If i get into that situation , will i be able to disassemble and
> reassemble the disk using the three disks i know are 'fine' and
> restart the rebuild process from where it stopped ? I have internal
> bitmap enabled.
>
> Is it possible to somehow freeze the rebuild process ? So i could
> pause the process for a few hours after 8 hours of work for example.
>
> The raid will be assembled but umounted during the rebuild proccess.
>
> I am using kernel 3.2.30.
>
> Thanks !!!
>
>
> []'s
> Salatiel
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