Am 09.01.2019 um 17:42 hat Paolo Bonzini geschrieben: > On 09/01/19 12:23, Kevin Wolf wrote: > > Also note that this is only metadata preallocation; full preallocation > > will still return allocated for the protocol layer and so it will always > > be slow. > > Full preallocation these days can create images with preallocated but > known-zero blocks, I think?
That would defeat one of the main purposes of preallocation because it would still require COW and metadata updates on the first write. If there is demand, we could add something like preallocation=data where data clusters are preallocated but COW/metadata updates still happen at runtime, but so far nobody has asked for it. Not sure when you would use it either. Kevin
