On Fri, Dec 8, 2017 at 1:35 AM Gianluca Cecchi <[email protected]> wrote:
> On Thu, Dec 7, 2017 at 9:33 PM, Nir Soffer <[email protected]> wrote: > >> >> For transferring images over http, there is no way to avoid sending >> unused blocks, except compression. >> > > OK, understood > > >>> Maybe this file was crated with preallocation=full? >>>> >>> >>> In virt-manager there is not this logic by default. >>> The default format is qcow2/sparse >>> When you create/add a disk you can choose "Select or create custom >>> storage": >>> >>> https://drive.google.com/file/d/1gAwjAG5aRFC5fFgkoZXT5wINvQnov88p/view?usp=sharing >>> >>> And then choose a format between: >>> raw, qcow, qcow2, qed, vmdk, vpc, vdi >>> >>> In my case it was the default one, so qcow2, as qemu-img correctly >>> detects. >>> >> >> I tested creating qcow2 files with virt manager, and it seems to use >> the preallocation=metadata by default (behind your back), I guess >> for improving performance in some cases. oVirt doe not use this >> option so we don't have this issue when downloading files. >> >> > Ah, ok. I didn't know about this preallocation option of qemu-img > Does your example mean that by default oVirt uses preallocation=off when > creating thin provisoned disks? > Correct, we use the default. > > >> I hope I convinced you this time ;-) >> >> Nir >> > > Yes :- ] and thanks for the deep an detailed explanation, Nir > > Thanks also to Eric for his comments in the other reply > > Gianluca > >
