On Wed, Aug 13, 2014 at 7:16 AM, Volodymyr Kostyrko <c.kw...@gmail.com> wrote:
> Hi all. > > There was a long time ago when I started to use pure zvol's as VirtualBox > disks. This way virtual machines were working faster due to default smaller > cluster size and I also can snapshot them and mount right from the OS. Too > bad this also required setting 'use host i/o cache' at storage controller > properties. Without that most guest OS would just break or hang. I've been using ZVOL's as Vbox disks for maybe @ 3 years including some exported as ISCSI. The break/hang you describe is totally unfamiliar to me even though my guests include various Linux distros, different versions/types of BSD, and several flavors of Windows. These included a mixture of i386/amd64 guests. I do not set "use host i/o cache" on any systems(not all have ZVOL snapshots but most do). > > Recently 10-STABLE was shown some improvements: > > 1. zfs set volmode=dev <zvol> > > Now you can mark zvol as a dev node preventing system from touching it. > Also this makes working with zvol simpler. > > 2. r269429 (MFC r269123): Implement separate I/O dispatch method for ZVOLs > in "dev" mode. > > After this one if you have zvol's marked as volmode=dev you can turn off > useHostIOCache for your virtual machines. And they would also work much > faster! But alas after that VirtualBox becomes unstable and your machines > can also fail on heavy IO. > 1 & 2 look very interesting. If that makes it into 10.1, I'll be giving it a whirl. -- Adam _______________________________________________ freebsd-emulation@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-emulation To unsubscribe, send any mail to "freebsd-emulation-unsubscr...@freebsd.org"
