On Tue, Oct 29, 2013 at 1:21 PM, Anand Avati <avati at gluster.org> wrote: > 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. > I see alignment issues and subsequent QEMU failure (pread() failing with EINVAL) when I use a file from XFS mount point (with sectsz=4k) as a virtio disk with cache=none QEMU option. However this failure isn't seen when I have sectsz=512. And all this is w/o gluster. So there seems to be some alignment issues even w/o gluster, I will debug more and get back. Jacob - In the first mail you sent on this subject, you mention that you don't see any issues when gluster volume is backed by ext4. Does this still hold true ? Regards, Bharata. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://supercolony.gluster.org/pipermail/gluster-users/attachments/20131030/26d1df01/attachment.html>
