[Gluster-users] Sparse Files and Heal

Lindsay Mathieson
Tue, 18 Nov 2014 12:05:06 -0000

I have a VM image which is a sparse file - 512GB allocated, but only 32GB used.


root at vnb:~# ls -lh /mnt/gluster-brick1/datastore/images/100
total 31G
-rw------- 2 root root 513G Nov 18 19:57 vm-100-disk-1.qcow2


I switched to full sync and rebooted.

heal was started on the image and it seemed to be just transfering the full file
from node
vnb to vng. iftop showed bandwidth at 500 Mb/s

Eventually the cumulative transfer got to 140GB which seemed odd as the real
file size was
31G. I logged onto the second node (vng) and the *real* file size  size was up
to 191Gb.

It looks like the heal is not handling sparse files, rather it is transferring
empty bytes to
make up the allocated size. Thats a serious problem for the common habit of over
committing your disk space with vm images. Not to mention the inefficiency.

thanks,

--
Lindsay
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://supercolony.gluster.org/pipermail/gluster-users/attachments/20141118/b10f5461/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part.
URL:
<http://supercolony.gluster.org/pipermail/gluster-users/attachments/20141118/b10f5461/attachment.sig>