On 09/27/2016 08:04 PM, Paolo Bonzini wrote: > > On 27/09/2016 15:28, Denis V. Lunev wrote: >> 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-de...@nongnu.org, qemu-block@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". >> 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. > You can add it through the filename path too, through a URI option > "nbd://...?zero-init=on". > > Paolo ha, cool idea! Thanks!
Den
