On 12/04/2009 10:22 PM, Chris Webb wrote: > I wonder how expensive it actually is to take and release the lock now? > Potentially it could already be quite cheap if corosync performs well and > given that dog is now in C... According to a corosync document, we can take 30,000 locks per second though it depends on the number of nodes, machine spec, etc. ftp://openais.org/presentations/inside-cpg.pdf I think locking performance is not a problem because we take a lock only when first opening VDI. >> I wonder whether sheepdog would be more easier to administrate. > > An additional concern is how painful it can be to get patches into qemu > nowadays, given the size of the project, especially getting them backported > to the various stable trees. I imagine the sheepdog client protocol and > feature-set will be faster moving than qemu's block interface, at least in > the short term. Okay, providing libsheepdog looks meaningful. I'll start considering what libsheepdog should export. Thanks, MORITA Kazutaka |