[sheepdog-users] Formatting an ext4 filesystem quickly

Liu Yuan namei.unix at gmail.com
Fri Apr 25 05:26:22 CEST 2014

On Thu, Apr 24, 2014 at 11:26:27AM -0500, Scott Devoid wrote:
> Hi all,
> I'm building out the sheepdog drivers for OpenStack Nova. In order to build
> ephemeral volumes for VMs we need to provision a vdi and format it with a
> labeled filesystem. I've gotten this to work with the sheepfs client on a
> reasonably sized cluster (20 nodes) and for a 10G volume, the format
> happens <1s. But the development cluster I have in Devstack is 3 nodes with
> -c local. In this scenario, sheepfs takes >5 min  to format the filesystem.

Hmm, this weird. Are the configurations of all the nodes same? I can imagine 20
nodes cluster faster than 3 nodes one, but wouldn't epxect such a big difference

Note, newer kernel gain writeback for FUSE, so formatting with recent kernel
or kernel that backports new patchset would gain much better performance.

> So I am wondering, is there a better way to format a vdi? OpenStack
> currently makes use of standard tools or libguestfs. Does sheepdog support
> either of these?

How do you think we can support libguestfs? I am not familiar with libguestfs,
so it would be nice if you can detail the support of it from sheepdog.

> Thanks,
> ~ Scott
> P.S. I need to sit down and write out what I'm doing for OpenStack &
> Sheepdog. You can look at a few of the review documents if you are
> interested:
> - https://review.openstack.org/#/c/82584/
> - https://review.openstack.org/#/c/74148/
> - https://review.openstack.org/#/c/89434/

Sounds nice, we always look forward someone working on the Openstack for
sheepdog. If you have any request for the support of Openstack from Sheepdog
community, feel free to drop a line.


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