On 08/18/2017 01:39 AM, Josef Bacik wrote:
[...]
> This is happening because the app (the guest OS in this case, we saw this a 
> lot
> with windows guests) is changing the pages while they are in flight.  We
> calculate the checksum of the page before it's written, so if it changes while
> in flight we'll end up with a csum mismatch.
> 
> To fix this change kvm to not use O_DIRECT or set NODATASUM on your qcow2 
> image.
> You'll have to re-create the image because NODATASUM won't apply to the 
> already
> invalid checksums.  Thanks,

Hi Josef,

could you elaborate: do you are saying that using O_DIRECT is incompatible with 
DATASUM ?

Let me know

BR
G.Baroncelli

> 
> Josef 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 


-- 
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D  17B2 0EDA 9B37 8B82 E0B5
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to