TOPIC:

Hello,

Some xenservers I need to use Halizard/iscsi on have thin provisioning (files), not LVM for backing VMs. Do you think it would be possible to just loop-mount a raw file and have DRBD work with that one instead of an LVM volume?

ops, sorry for opening this topic in the wrong category..

We have not tried this in a thin provisioned environment, but, in theory, I would expect it to work. Since DRBD is replicating a raw block device, it is not aware of any partitioning or files that are written to it. As far as XenServer is concerned, the storage simply looks like an iSCSI SR and it really does not matter whether disk images are occupying LVs or are thin provisioned disk files.

The piece we are not clear on in this environment is whether XenServer manages the iSCSI SR as an LVM VolumeGroup (as is the case with thick provisioning). if it does, this should be fairly straightforward. If not, some tweaks may be necessary.

We would be very interested to hear about your test results in this environment so that others can benefit.

Thanks for the reply.
I'll give it a try and let you know.

I'm already hitting annoying things due to the limited capability of Xenserver (no ext4, no fallocate, waiting for DD to fill 2 TB file etc), need to work around these first.

Yeah, I let this idea go, Xenserver6's dom0 is way too limited at this point to do things like this.
Maybe future versions will be more capable.