[Sheepdog] Performance of sheepdog

[Piavlo]

 Hi,

PCextreme B.V. - Wido den Hollander wrote:
> Hi,
>
> I have been following sheepdog's mailinglist ever since i saw a newspost
> on www.linux-kvm.com, but what kept me wondering was the performance.
>   
I have not done any performance testing yet, mainly since the sheepdog
patched kvm does not work for me.
So currently I can only test image creation performance.

But if disk performance is  important for you probably need to separate
the host running the KVM VMs completely
from the VMs image storage device (like done with iSCSI or AOE but not
DRBD) since otherwise the KVM host will probably be throttled
by random disk access generated by your VMs (unless you have just a few
VMs) plus occasional overhead while new images are being created.

AFAIU with current sheepdog  implementation the KVM host MUST be part of
the sheepdog storage cluster.
So it would be nice if sheepdog client and sheepdog server could be run
on different hosts - currently one can overcome this
limitation by keeping the btrfs system not on local disk but on
iSCSI/AOE or any other SAN device.
But addition of another SAN technology complicates the overall solution
and reduces stability.
So if sheepdog could do the job alone it would be much better.
> At the moment i don't have 3 servers with SMX/VMX to spare for testing
> sheepdog, so i haven't been able to test sheepdog jet.
>
> At the company i work we use a lot of KVM, our redundant storage is
> build on top of iSCSI and DRBD. The performance is great (IOps), so
> that's not an issue, but the waste of hardware is (Master/Slave setup).
>
>   
AFAIU you have combined iSCSI with DRBD , thus the Master/Slave comes
from DRBD.
With sheepdog you still have hardware overhead since you need to run at
least two sheepdog
server hosts - which for performance reasons should be separated from
the sheepdog clients (the KVM hosts).

Alex
> The question that kept me busy was, how is the performance of sheepdog?
> Yes, i understand that sheepdog and btrfs are still under heavy
> development, but in this stage, how is it performing?
>
> Since sheepdog really seems THE solution for building a real cloud with
> KVM.
>
> I'll keep following sheepdog closely and try to set-up a test
> envirioment asap!
>
>