[mythtv-users] semiOT: minor emergency, raid array's contents deleted

Brian Wood beww at beww.org
Mon Dec 7 17:21:50 UTC 2009


On Monday 07 December 2009 10:16:27 am Steven Adeff wrote:
> On Mon, Dec 7, 2009 at 12:03 PM, John Drescher 
<drescherjm at gmail.com> wrote:
> > On Mon, Dec 7, 2009 at 11:56 AM, Steven Adeff 
<adeffs.mythtv at gmail.com> wrote:
> >> so here's a weird one...
> >>
> >> was watching some tv then shutdown my frontend, ssh'd into the 
backend
> >> and noticed that both my raid arrays are now "empty". the 
filesystems,
> >> which are JFS, check out as fine, but both, on seperate computers, are
> >> now both completely blank. absolutely no idea how this happened, but
> >> I'm hoping someone here has an idea as to what may have happened 
and
> >> if there is a way to recover all my lost data?
> >
> > With linux software raid recovery is usually possible. I have not seen
> > a case where I could not recover and I run dozens of arrays at work.
> >
> > Your description of the problem is very unclear.
> >
> > can you post the output of
> >
> > cat /proc/mdstat
> >
> > Should look something like this:
> >  # cat /proc/mdstat
> > Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
> > md0 : active raid5 sx8/1[0] sx8/4[4] sx8/3[3] sx8/5[2] sx8/2[1]
> >      976793600 blocks level 5, 256k chunk, algorithm 2 [5/5] [UUUUU]
> >
> > md1 : active raid6 sx8/6[0] sx8/15[9] sx8/14[8] sx8/12[6] sx8/11[5]
> > sx8/10[4] sx8/9[3] sx8/8[2] sx8/7[1]
> >      1953587200 blocks level 6, 512k chunk, algorithm 2 [10/9]
> > [UUUUUUU_UU]
> >
> > unused devices: <none>
> >
> > well without the bad drive. I am working on that at the minute. I have
> > to either wait till everyone goes home or reboot the server to remove
> > the 5 drives from md0 so that I can replace them with 6x1TB drives and
> > use one of the old 250GB SATA1 disks in md1..
> >
> > John
> 
> the array looks fine,
> Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0]
> [raid1] [raid10]
> md0 : active raid5 sda[0] sde1[5] sdf1[4] sdd1[3] sdc1[2] sdb1[1]
>       1465248000 blocks level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU]
> 
> unused devices: <none>
> 
> and the filesystems come back as "clean"
> # jfs_fsck /dev/md0
> jfs_fsck version 1.1.12, 24-Aug-2007
> processing started: 12/7/2009 12.6.12
> Using default parameter: -p
> The current device is:  /dev/md0
> Block size in bytes:  4096
> Filesystem size in blocks:  366312000
> **Phase 0 - Replay Journal Log
> Filesystem is clean.
> 
> but it shows up as being empty. as if someone did a "rm * -f", which I
> didn't do explicitly, and it blanked both my array's, which makes me
> think something like a "rm * -rf" was run in where I mount them, I
> just don't know how since I haven't done anything that I can think
> would cause that, I've just been playing around with getting a
> diskless frontend going for the last week.
> 

Sure sounds like the files were deleted, something RAID does not protect 
against.

This is why RAID is not a substitute for regular backups.

But you knew that :-)

I'm not familiar enough with JFS to know if an "undelete" is possible.


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