[Sheepdog] Dividing objects across disks

[MORITA Kazutaka]

At Mon, 8 Aug 2011 16:52:10 +0100,
Brian Candler wrote:
> 
> I'm thinking of using Mac Mini servers as KVM/Sheepdog nodes.
> 
> The Mac Mini server has two hard drives in it, and I'd like the Sheepdog
> objects to be distributed between these to benefit from the extra read/write
> performance.  However I don't want them to be considered as two separate
> Sheepdog nodes - data needs to be replicated to separate physical nodes.
> 
> I also don't want to use RAID0 because it would be hard to arrange that the
> Sheepdog 4MB data chunks are aligned to the RAID0 stripes.  If this isn't
> done, then performance would be worse than with a single disk.
> 
> Ideally, I think I'd like to mount /store_device/0 and store_device/1 as two
> separate filesystems, and have Sheepdog distribute objects between them.  Is
> there a simple way to do this?

Even if you run multiple daemons on the same node, you can replicate
the data to separate nodes with a '--zone' option (you need to get the
latest codes from the git repository to test this feature).

For example:

  [on node A]
  $ sheep /store_device/0 --zone 1
  $ sheep /store_device/1 --zone 1

  [on node B]
  $ sheep /store_device/0 --zone 2
  $ sheep /store_device/1 --zone 2

  [on node C]
  $ sheep /store_device/0 --zone 3
  $ sheep /store_device/1 --zone 3

The data is not replicated in the same zone, so you can ensure that
the data is replicated to separate physical nodes.

Does this work for you?


Thanks,

Kazutaka