Re: Got 10 csum errors according to dmesg but 0 errors according to dev stats

[Philip Seeger <p0h0i0l0i0p@gmail.com>]

The SATA controller used for the virtual hard drive of this vm does not 
have host caching enabled (checkbox not checked). So, no, VirtualBox 
should not be using any form of disk caching.

Also, there is no Windows involved.

Philip

On 05/12/2015 03:04 AM, Paul Jones wrote:
>> -----Original Message-----
>> From: linux-btrfs-owner@vger.kernel.org [mailto:linux-btrfs-
>> owner@vger.kernel.org] On Behalf Of Philip Seeger
>> Sent: Tuesday, 12 May 2015 10:15 AM
>> To: linux-btrfs@vger.kernel.org
>> Subject: Re: Got 10 csum errors according to dmesg but 0 errors according to
>> dev stats
>>
>>> Sounds like you are having errors in your RAM, CPU, motherboard, or
>>> hard drive cabling.  Turn the machine off ASAP and plug the disks into
>>> a different system, if you keep it running you will make it worse.
>>>
>> I know it sounds like it, but the host is fine. The host filesystem (on which the
>> vm virtual hdd resides) is healthy. Other vms are running on the same host,
>> no problems there. Just to be sure, I will run memtest, but I'm pretty sure
>> that's not it. The system is under high load a lot, but I don't think btrfs would
>> fail because of a slow system.
>>
>> So I have deleted all those corrupted files in this Arch vm, ran a scrub, 0
>> errors, all fixed. I restored them, fixed some other things and now - I get
>> checksum errors again. Interestingly, it looks like the corruption is not
>> happening randomly, because the same sqlite files are affected under
>> ~/.mozilla/ and exactly one library file (ghostscript).
>> Meanwhile, other vms (not Arch but Fedora and Debian) are running without
>> a problem (one of them using btrfs as well).
>>
>> Is it possible that systemd isn't unmounting the filesystem properly, so it gets
>> corrupted on shutdown? (Juest a wild guess.) Although I'm not sure if all this
>> happened between reboots.
> Are you using KVM with some form of disk caching? I had a windows vm that was constantly creating errors on the host filesystem (btrfs) somewhere within the disk image. I changed the caching option (I can't remember from/to what) and it fixed the error. It didn't seem to be causing any errors on the windows guest, but it's windows so you never know :)
>
> Paul.