> > 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).
