[Sheepdog] faq

[MORITA Kazutaka]

At Sun, 14 Aug 2011 15:39:30 +0200,
Valerio Pachera wrote:
> 
> The command 'collie cluster format --copies=n' have to be run only one
> time on any of the computer that is running corosync?
> -- I already know the answer: yes --
> 
> Can I add more time the same node? E.g.
> # sheep /mnt/disk1
> # sheep /mnt/disk2

Yes.

> 
> Does the data directory used by sheepdog to be empty? (sheep /store_dir)?

If the node was in the cluster before, it can contain old Sheepdog
data.  Otherwise, the directory must be empty.

> 
> Is it possible to have store directory of different sizes (E.g. 50G and 500G)?

Currently, no.  A similar discussion is in the follwoing thread:
  http://lists.wpkg.org/pipermail/sheepdog/2011-August/001145.html

> If yes, think to the simple scenario of two nodes, do I get any alert
> form sheepdog when the small node is getting full?
> If no, what happens?

Write operations from VMs will result in I/O errors (Sheepdog returns
a disk full error).

> 
> I compiled the latest version of qemu-kvm, but I'm running an "old"
> kernel (2.6.32), so the kvm module is not the latest one.
> May that be a problem for sheepdog?

Sheepdog doesn't depend on KVM support.  If you can run the qemu-kvm
on the kernel, Sheepdog also should work.

Thanks,

Kazutaka