Re: [Qemu-devel] [PATCH] sheepdog: implement direct write semantics

[Liu Yuan]

On 01/09/2013 06:25 PM, Paolo Bonzini wrote:
> But why is it useful to force-disable writeback caching?  Do you have
> any performance numbers?

This is not related to performance. What I want is to allow users to
choose Sheepdog cache mode (writethrough/writeback/directio) from cache=xxx.

Obviously writeback mode show much better write performance over
writethrough cache in Sheepdog. NOTE: writethrough cache in Sheepdog is
a readonly cache which is always consistent with cluster data thus need
no flush at all. This is to boost read performance for read intensive
Guest over Sheepdog iamges.

Thanks,
Yuan