The sheepdog block driver for qemu has been merged into mainline qemu providing access to sheepdog’s distributed storage system. Sheepdog is the first driver for a distributed file system to be included into upstream qemu ( I don’t consider nbd to be a distributed file system ). The sheepdog team has been been submitting patches since last year for inclusion into qemu.

Since then, there have been a few revisions and just a few days ago it was merged into upstream qemu. You now have native access to the client block drivers in qemu. What is also noteworthy is that qemu is currently the only client for the sheepdog distributed file system. With the inclusion into upstream qemu, you can expect to see these drivers merged into qemu-kvm very soon.

Using the sheepdog distributed file system requires the following:

• Three or more x86-64 machines
• Corosync cluster engine

A typical session using qemu with sheepdog will look like the following example taken from the sheepdog website. On the cluster nodes:

Install corosync on the nodes

yum install corosync          <--------- install corosync
service corosync start        <--------- start the daemon

Once qemu with sheepdog drivers are released in future you simply need to install qemu or qemu-kvm.

yum install qemu-kvm          <-------- install qemu/kvm

Until the sheepdog drivers have been merged into qemu-kvm, you’ll have to use the instructions at the following page.

http://www.osrg.net/sheepdog/usage.html

Run the following commands to start your qemu session using the sheepdog distributed filesystem.

sheep /store                       <---- launch on each cluster node
collie cluster format --copies=3   <----- specify data redundancy
qemu-img create sheepdog:Alice 256G   <----- create the disk image on sheepdog
qemu-system-x86_64 sheepdog:Alice    <----- start qemu/kvm

The sheepdog website has been updated and provides some good documentation on getting started with sheepdog including how to convert images to sheepdog format and using snapshots with sheepdog. See the following page on getting started with sheepdog with the qemu client.

http://www.osrg.net/sheepdog/usage.html