Re: Md corruption using RAID10 on linux-2.6.21

["Don Dupuis" <dondster@gmail.com>]

On 5/16/07, Don Dupuis <dondster@gmail.com> wrote:
> On 5/16/07, Neil Brown <neilb@suse.de> wrote:
> > On Wednesday May 16, dondster@gmail.com wrote:
> > ...
> > >
> > > The problem arises when I do a drive removal such as sda and then I
> > > remove power from the system. Most of the time I will have a corrupted
> > > partition on the md device. Other corruption will be my root partition
> > > which is an ext3 filesystem. I seem to have a better chance of booting
> > > a least 1 time with no errors with bitmap turned on, but If I repeat
> > > the process, I will have corruption as well. Also with bitmap turned
> > > on, adding the new drive into the md device will take way to too long.
> > > I only get about 3MB per second on the resync. With bitmap turned off,
> > > I will get between 10MB to 15MB resync rate. Has anyone else seen this
> > > behavior, or is this situation is no tested very often? I would think
> > > that I shouldn't get corruption with this raid  setup and jornaling of
> > > my filesytems? Any help would be appreciated.
> >
> >
> > The resync rate should be the same whether you have a bitmap or not,
> > so that observation is very strange.  Can you double check, and report
> > the contents of "/proc/mdstat" in the two situations.
> >
> > You say you have corruption on your root filesystem.  Presumably that
> > is not on the raid?  Maybe the drive doesn't get a chance to flush
> > it's cache when you power-off.  Do you get the same corruption if you
> > simulate a crash without turning off the power. e.g.
> >    echo b > /proc/sysrq-trigger
> >
> > Do you get the same corruption in the raid10 if you turn it off
> > *without* removing a drive first?
> >
> > NeilBrown
> >
> Powering off with all drives will not have corruption. When I have a
> drive missing and the md device does a full resync, I will get the
> corruption. Usually the md partition table is corrupt or gone. and
> with the first drive gone it happens more frequently. If the partition
> table is not corrupt, then the rootfilesystem or one of the other
> filesystems on the md device will be corrupted. Yes my root filesystem
> is on the raid device. I will update with the bitmap resync rate stuff
> later.
>
> Don
>
Forgot to tell you that I have the drive write cache disabled on all my drives.

Don