[Gluster-users] KVM guest I/O errors with xfs backed gluster volumes

[Jacob Yundt]

>
> Looks like what is happening is that qemu performs ioctls() on the backend to query logical_block_size (for direct IO alignment). That works on XFS, but fails on FUSE (hence qemu ends up performing IO with default 512 alignment rather than 4k).
>
> Looks like this might be something we can enhance gluster driver in qemu. Note that glusterfs does not have an ioctl() FOP, but we could probably wire up a virtual xattr call for this purpose.
>
> Copying Bharata to check if he has other solutions in mind.
>
> Avati
>
>
>
> On Tue, Oct 29, 2013 at 12:13 AM, Anand Avati <avati at gluster.org> wrote:
>>
>> What happens when you try to use KVM on an image directly on XFS, without involving gluster?
>>
>> Avati
>>

Avati-

Thanks for finding this.  Unfortunately, my KVM hosts (gluster
clients) either don't have local disks or their local disks have 512
byte sectors.

Let me know if I can provide any additional information.

-Jacob