Am 27.09.2016 um 20:59 hat Denis V. Lunev geschrieben: > 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-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". > >> 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!
What's the advantage of writing "?zero-init=on" instead of ",zero-init=on"? Doesn't it only add more string parsing code for no benefit? Kevin
