So currently blktap2 can be used outside of Xen, but I don''t think many people do that. I have a use case now where I must support KVM (I currently run only Xen servers) and found the disk snapshotting to be not as nice as what I can do with vhd''s in blktap2 (and a half). So I was thinking of actually trying to just run blktap for the storage. So I''m pretty pleased with that solution and functionally it works just fine. The problem now is blktap3. So is there going to be any way to use blktap3 outside of Xen? If blktap3 is the future I probably won''t continue with my blktap/kvm solution. Thanks, Darren _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
On Sat, Nov 24, 2012 at 7:31 AM, Darren Shepherd <darren.s.shepherd@gmail.com> wrote:> So currently blktap2 can be used outside of Xen, but I don''t think many > people do that. I have a use case now where I must support KVM (I currently > run only Xen servers) and found the disk snapshotting to be not as nice as > what I can do with vhd''s in blktap2 (and a half). So I was thinking of > actually trying to just run blktap for the storage. So I''m pretty pleased > with that solution and functionally it works just fine. > > The problem now is blktap3. So is there going to be any way to use blktap3 > outside of Xen? If blktap3 is the future I probably won''t continue with my > blktap/kvm solution.Since AFAIK blktap3 is not even in xen-unstable, personally I''d just use something with more userbase and better tested. Something like zfsonlinux. It has support for sparse zvols, as well as snapshot and clones. -- Fajar
On Nov 23, 2012, at 4:39 PM, "Fajar A. Nugraha" <list@fajar.net> wrote:> On Sat, Nov 24, 2012 at 7:31 AM, Darren Shepherd > <darren.s.shepherd@gmail.com> wrote: >> So currently blktap2 can be used outside of Xen, but I don''t think many >> people do that. I have a use case now where I must support KVM (I currently >> run only Xen servers) and found the disk snapshotting to be not as nice as >> what I can do with vhd''s in blktap2 (and a half). So I was thinking of >> actually trying to just run blktap for the storage. So I''m pretty pleased >> with that solution and functionally it works just fine. >> >> The problem now is blktap3. So is there going to be any way to use blktap3 >> outside of Xen? If blktap3 is the future I probably won''t continue with my >> blktap/kvm solution. > > Since AFAIK blktap3 is not even in xen-unstable, personally I''d just > use something with more userbase and better tested. Something like > zfsonlinux. It has support for sparse zvols, as well as snapshot and > clones. > > -- > FajarI''m using blktap2, but that''s really besides the point. The more direct question is going forward with blktap3 is there going to be a way to see the blktap device as a block device in dom0? Darren
On Sat, 2012-11-24 at 01:08 +0000, Darren Shepherd wrote:> The more direct question is going forward with blktap3 is there going > to be a way to see the blktap device as a block device in dom0?There will have to be, e.g. to support pygrub and similar uses. I''m not sure what form this will eventually take though (CCing Thanos, blktap3 maintainer). Ideas which I''ve heard floating about are to have tapdisk export an nbd server or supporting running a vbd device in dom0 in a loopback type mode. Ian.
> -----Original Message----- > From: Ian Campbell > Sent: 26 November 2012 10:45 > To: Darren Shepherd > Cc: Fajar A. Nugraha; xen-devel@lists.xen.org; Thanos Makatos > Subject: Re: [Xen-devel] blktap3 as a block device? > > On Sat, 2012-11-24 at 01:08 +0000, Darren Shepherd wrote: > > The more direct question is going forward with blktap3 is there going > > to be a way to see the blktap device as a block device in dom0? > > There will have to be, e.g. to support pygrub and similar uses. > > I''m not sure what form this will eventually take though (CCing Thanos, > blktap3 maintainer). Ideas which I''ve heard floating about are to have > tapdisk export an nbd server or supporting running a vbd device in dom0 > in a loopback type mode.Yes this is one of the possibilities; this functionality is already on blktap2.5 (where blktap3 is based on). Another idea could be to use both blkfront and tapdisk on dom0, haven''t considered that thoroughly though.> > Ian. >
On 26/11/12 11:54, Thanos Makatos wrote:> > >> -----Original Message----- >> From: Ian Campbell >> Sent: 26 November 2012 10:45 >> To: Darren Shepherd >> Cc: Fajar A. Nugraha; xen-devel@lists.xen.org; Thanos Makatos >> Subject: Re: [Xen-devel] blktap3 as a block device? >> >> On Sat, 2012-11-24 at 01:08 +0000, Darren Shepherd wrote: >>> The more direct question is going forward with blktap3 is there going >>> to be a way to see the blktap device as a block device in dom0? >> >> There will have to be, e.g. to support pygrub and similar uses. >> >> I''m not sure what form this will eventually take though (CCing Thanos, >> blktap3 maintainer). Ideas which I''ve heard floating about are to have >> tapdisk export an nbd server or supporting running a vbd device in dom0 >> in a loopback type mode. > > Yes this is one of the possibilities; this functionality is already on blktap2.5 (where blktap3 is based on). > > Another idea could be to use both blkfront and tapdisk on dom0, haven''t considered that thoroughly though.From my point of view using blkfront on Dom0 should be used instead of nbd. nbd is Linux specific, on the other hand all Dom0s have a blkfront implementation.
On Sat, 24 Nov 2012, Darren Shepherd wrote:> On Nov 23, 2012, at 4:39 PM, "Fajar A. Nugraha" <list@fajar.net> wrote: > > > On Sat, Nov 24, 2012 at 7:31 AM, Darren Shepherd > > <darren.s.shepherd@gmail.com> wrote: > >> So currently blktap2 can be used outside of Xen, but I don''t think many > >> people do that. I have a use case now where I must support KVM (I currently > >> run only Xen servers) and found the disk snapshotting to be not as nice as > >> what I can do with vhd''s in blktap2 (and a half). So I was thinking of > >> actually trying to just run blktap for the storage. So I''m pretty pleased > >> with that solution and functionally it works just fine. > >> > >> The problem now is blktap3. So is there going to be any way to use blktap3 > >> outside of Xen? If blktap3 is the future I probably won''t continue with my > >> blktap/kvm solution. > > > > Since AFAIK blktap3 is not even in xen-unstable, personally I''d just > > use something with more userbase and better tested. Something like > > zfsonlinux. It has support for sparse zvols, as well as snapshot and > > clones. > > > > -- > > Fajar > > I''m using blktap2, but that''s really besides the point. > > The more direct question is going forward with blktap3 is there going to be a way to see the blktap device as a block device in dom0?Yes, setting up a local frontend/backend connection in dom0: the backend is blktap3, the frontend is the blkfront driver in the dom0 kernel