Re: [Qemu-devel] [RFC 0/8] block: Live backup prototype

[Dietmar Maurer]

> > We track zero blocks at 4KB level to get small backup files. Restore
> > can handle those blocks differently, either pre-allocate or create holes. 
> > That
> can even be a restore option.
> 
> You are right, the behavior can be set at restore time.
> 
> I'm curious how much of a win the 4 KB zero detection is on random Linux or
> Windows guest images.  Have you collected numbers?

Well, seems that it does not help much - it saves about 0.2% space. So maybe we
can remove that feature (and increase address space in the VMA format instead).