[linux-lvm] Random file system errors
Clyde E. Kunkel
rascal.jumper-747 at cox.net
Tue Apr 28 14:41:24 UTC 2009
On 04/27/2009 09:52 PM, Gaute Lund wrote:
> I have searched the web and the mailing list without finding anything
> similar to this.
>
> At home I have an LVM setup. Reading data gives random errors. I only
> recently discovered it's an LVM issue. I think.
>
> The issue: If I md5sum largeish files, or test archives, I sometimes get
> errors or randomly different md5sums. Like now, I have 11 folders, all with
> rar files in parts: some 300 15MB pieces in 6 folders/sets, totaling 4,2GB,
> and 560 50MB pieces in 5 folders/sets, totaling 23G.
>
> OK, so I "rar t" all of these 5 times over. Errors pop up randomly, 52 times
> in the 50MB pieces, 10 times in the 15MB pieces. That's about 1 error for
> every 2,1GB of data read. Md5suming multiple files gives about the same
> error rate.
>
> If I run repeated test on a rar set small enough to fit in cache mem, I get
> errors, but they are indentical with each run.
>
> Is it really an lvm problem? Well, I have created new LVs and use different
> filesystems, ext3, xfs, jfs - they're all the same. If I create an md on
> some other disks, and put a filesystem on it, without LVM, no problems.
>
> I can't find any other errors, in any logs or dmesg. The errors weren't
> there to begin with, they came at one point and got worse. It took a while
> before I realized it was a generic disk problem, and for a period I kind of
> gave up on it. So it's been there for ... maybe six months?
>
> The VG consist of two software RAID 5 md's, one consisting of four 200GB
> IDEs, one of five 500GB SATAs, yielding av VG totaling 2,37TB. Other
> hardware is 4GB memory and a Core 2 Duo 6600 CPU.
>
> Machine runs Ubuntu 8.10 with kernel 2.6.27-11, and
> LVM version: 2.02.39 (2008-06-27)
> Library version: 1.02.27 (2008-06-25)
> Driver version: 4.14.0
>
> But the VG was originally created long ago, on LVM1 even.
>
> Well, I guess that's it. Any other information that could be helpful? Any
> way I could debug this?
>
> Best regards
> Gaute Lund
>
I am seeing the same thing with large (distros on DVDs) ISO files also.
Running md5sum or sha1sum on the file gives different results each time
and burning the iso gives a dvd that contains files with errors. I ran
memory tests over night and all was good. I turned on smartd checking
and ran disk checks and all is ok and I continue to look for disk errors
on a periodic basis and all is well.
The linux system is Fedora rawhide, but the problem also exists in
Fedora 9 and 10. The files are being downloaded with wget to a Download
directory on my home directory which is an ext3 LV mounted on an ext4
home filesystem. Wgeting to a standard non-LV ext3 parition results in
good isos which demonstrate consistent sha1sums. If I cp the good iso
to the LV Download directory, problems again occur. So far the problem
only manifests with dvd size iso files. CD size iso files are fine.
I first noticed this problem several months ago, but have not bz'd it
since I cannot yet for sure say it is LVM causing the problem. However,
I think at this point I have eliminated wget as the problem but not
ext4. I need to create an ext3 LV for / to test on.
Any guidance on error capturing or any testing features of LVM2 that can
be turned on?
Thanks.
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