On 09/27/2016 03:07 PM, Paolo Bonzini wrote: > > ----- Original Message ----- >> From: "Denis V. Lunev" <d...@virtuozzo.com> >> To: "Paolo Bonzini" <pbonz...@redhat.com> >> Cc: "Vladimir Sementsov-Ogievskiy" <vsement...@virtuozzo.com>, >> qemu-devel@nongnu.org, qemu-bl...@nongnu.org, >> nbd-gene...@lists.sourceforge.net, a...@alex.org.uk, ebl...@redhat.com, >> kw...@redhat.com, stefa...@redhat.com, >> w...@uter.be >> Sent: Tuesday, September 27, 2016 12:25:54 PM >> Subject: Re: [PATCH] proto: add 'shift' extension. >> >> On 09/27/2016 01:15 PM, Paolo Bonzini wrote: >>>> We could go in a different direction and export flag >>>> 'has_zero_init' which will report that the storage is >>>> initialized with all zeroes at the moment. In this >>>> case mirroring code will not fall into this >>>> branch. >>> Why don't you add the zero_init flag to QEMU's NBD driver instead? >> for all cases without knowing real backend on the server side? >> I think this would be wrong. > Add it to the command line, and leave it to libvirt or the user to > pass "-drive file.driver=nbd,...,file.zero-init=on". > > Paolo I have started with something very similar for 'drive-mirror' command. We have added additional flag for this to improve migration speed and this was rejected.
Den
