Re: Raid over USB disks and eject

[NeilBrown <neilb@suse.de>]

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On Mon, 12 Nov 2012 16:07:28 +0000 Benjamin ESTRABAUD <be@mpstor.com> wrote:

> 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

"idle" is not sufficient.  It will stop the recovery, but then it will
immediately start again.
You need "frozen".

NeilBrown


> 
> 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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> 
> 
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