[sheepdog] [Sheepdog]Openstack support sheepdog matters?

[harryxiyou]

On Fri, Jan 18, 2013 at 5:42 PM, MORITA Kazutaka
<morita.kazutaka at gmail.com> wrote:
> At Fri, 18 Jan 2013 14:00:35 +0800,
[...]
> What you want is SheepdogISCSIDriver like LVMISCSIDriver or
> NetAppISCSIDriver?

Yup, i need SheepdogISCSIDriver.

>There is no such driver, but it's possible to implement.

But why Sheepdog driver was not implemented by SheepdogISCSIDriver way but
by the QEMU/Libvirt way?
Could you please tell me the differences between these two ways? From the page
http://wiki.openstack.org/SheepdogSupport , i find the Rationale like following.

"Current implementation of volumes  (iSCSI/AoE with LVM) is not fit for IaaS.
1, the architecture is not scalable in capacity and performance
2, LVM machine could become a SPOF
3, If we take many LVM snapshots, the performance of volumes becomes terrible".

If the Rationale is the SheepdogISCSIDriver's disadvantages? Or
SheepdogISCSIDriver
has some other disadvantages so that we use QEMU/Libvirt way instead?


-- 
Thanks
Harry Wei