[Qemu-devel] [migration] questions about removing the old block-migration code
Hi, Juan I read below words on the report of , We were going to remove the old block-migration code Then people fixed it Good: it works now Bad: We have to maintain both It uses the same port than migration You need to migrate all/none of block devices The old block-migration code said above is that in block-migration.c? What are the reasons of removing the old block-migration code? Buggy implementation? Or need to migrate all/none of block devices? What's the substitutional method? drive_mirror? Thanks, Zhang Haoyu
Re: [Qemu-devel] [migration] questions about removing the old block-migration code
On Sun, Nov 03, 2013 at 04:01:36AM +, Zhanghaoyu (A) wrote: > I read below words on the report of (May 29, 2013)>, > We were going to remove the old block-migration code > Then people fixed it > Good: it works now > Bad: We have to maintain both > It uses the same port than migration > You need to migrate all/none of block devices > > The old block-migration code said above is that in block-migration.c? Yes. > What are the reasons of removing the old block-migration code? Buggy > implementation? Or need to migrate all/none of block devices? Buggy and tightly coupled with the live migration code, making it hard to modify either area independently. > What's the substitutional method? drive_mirror? drive_mirror over NBD is an alternative. There are security and integration challenges with those approaches but libvirt has added drive-mirror block migration support. Stefan
Re: [Qemu-devel] [migration] questions about removing the old block-migration code
>> I read below words on the report of > forecast (May 29, 2013)>, We were going to remove the old >> block-migration code Then people fixed it >> Good: it works now >> Bad: We have to maintain both >> It uses the same port than migration >> You need to migrate all/none of block devices >> >> The old block-migration code said above is that in block-migration.c? > >Yes. > >> What are the reasons of removing the old block-migration code? Buggy >> implementation? Or need to migrate all/none of block devices? > >Buggy and tightly coupled with the live migration code, making it hard to >modify either area independently. Thanks a lot for explaining. Till now, we still use the old block-migration code in our virtualization solution. Could you detail the bugs that the old block-migration code have? Thanks, Zhang Haoyu > >> What's the substitutional method? drive_mirror? > >drive_mirror over NBD is an alternative. There are security and integration >challenges with those approaches but libvirt has added drive-mirror block >migration support. > >Stefan
Re: [Qemu-devel] [migration] questions about removing the old block-migration code
On Fri, Nov 08, 2013 at 01:17:17AM +, Zhanghaoyu (A) wrote: > >> I read below words on the report of >> forecast (May 29, 2013)>, We were going to remove the old > >> block-migration code Then people fixed it > >> Good: it works now > >> Bad: We have to maintain both > >> It uses the same port than migration > >> You need to migrate all/none of block devices > >> > >> The old block-migration code said above is that in block-migration.c? > > > >Yes. > > > >> What are the reasons of removing the old block-migration code? Buggy > >> implementation? Or need to migrate all/none of block devices? > > > >Buggy and tightly coupled with the live migration code, making it hard to > >modify either area independently. > > Thanks a lot for explaining. > Till now, we still use the old block-migration code in our virtualization > solution. > Could you detail the bugs that the old block-migration code have? Please use git log block-migration.c to see bugs that have been fixed. The basic problem is that block-migration.c hasn't been actively maintained or used much. My impression is that the newer block migration approach using drive-mirror now has more developer and testing focus (see libvirt if you're curious how drive-mirror can be orchestrated). Stefan
