Hi,
I''m going to make a live migration of some Xen guests from a machine
to another. At the moment I''m preparing both systems, syncing software
versions, while I read some documentation about the live migration
process.
The process looks simple, but I''m still have only one question. Let me
explain:
I have a guest on my Xen host 1 that have 3 virtual partitions that
are mapped to 3 logical volumes of the host, as follows:
Guest virtual partition Guest mount point Host physical partition
/dev/sda1 /
/dev/xenvg/apache-root
/dev/sda2 swap
/dev/xenvg/apache-swap
/dev/sda3 /var
/dev/xenvg/apache-var
On the Xen host 2, I created the same physical partitions existing on
Xen host 1, with same name and locations.
So, at the moment I think my next steps are:
1. Copy the config file for the guest from Xen host 1 to Xen host 2
2. Execute on Xen host 1:
# xm migrate --live guest host2
Is that right or is something missing?
Note.: I read many docs, and all they say that I need to make image
files available on both Xen hosts. But I''m not using image files, but
logical volumes...
Thanks,
Davidson Paulo
On Fri, Mar 23, 2007 at 05:13:25PM -0300, Davidson Rodrigues Paulo wrote:> I have a guest on my Xen host 1 that have 3 virtual partitions that > are mapped to 3 logical volumes of the host, as follows: > > Guest virtual partition Guest mount point Host physical > partition > /dev/sda1 / > /dev/xenvg/apache-root > /dev/sda2 swap > /dev/xenvg/apache-swap > /dev/sda3 /var > /dev/xenvg/apache-var > > On the Xen host 2, I created the same physical partitions existing on > Xen host 1, with same name and locations.Nahh, that won''t work. For migration you need the same volumes, i.e. the simplest is to use NFS or GFS, but you definitely need network file systems for migration to really work. Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ veillard@redhat.com | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/
On Fri, Mar 23, 2007 at 05:13:25PM -0300, Davidson Rodrigues Paulo wrote:> Hi, > > I''m going to make a live migration of some Xen guests from a machine > to another. At the moment I''m preparing both systems, syncing software > versions, while I read some documentation about the live migration > process. > > The process looks simple, but I''m still have only one question. Let me > explain: > > I have a guest on my Xen host 1 that have 3 virtual partitions that > are mapped to 3 logical volumes of the host, as follows: > > Guest virtual partition Guest mount point Host physical > partition > /dev/sda1 / > /dev/xenvg/apache-root > /dev/sda2 swap > /dev/xenvg/apache-swap > /dev/sda3 /var > /dev/xenvg/apache-var > > On the Xen host 2, I created the same physical partitions existing on > Xen host 1, with same name and locations.Urm, and how exactly are you expecting the data within those partitions to replicate itself across machines... ?!?! You need to have either a shared block device (SAN, iSCSI, GNBD) with a cluster filesystem (GFS2, OCFS), or use a plain file as your disk backend locating it on NFS.> Is that right or is something missing?All your data is missing :-) Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
On Mon, Mar 26, 2007 at 09:06:34AM -0400, Daniel Veillard wrote:> On Fri, Mar 23, 2007 at 05:13:25PM -0300, Davidson Rodrigues Paulo wrote: > > I have a guest on my Xen host 1 that have 3 virtual partitions that > > are mapped to 3 logical volumes of the host, as follows: > > > > Guest virtual partition Guest mount point Host physical > > partition > > /dev/sda1 / > > /dev/xenvg/apache-root > > /dev/sda2 swap > > /dev/xenvg/apache-swap > > /dev/sda3 /var > > /dev/xenvg/apache-var > > > > On the Xen host 2, I created the same physical partitions existing on > > Xen host 1, with same name and locations. > > Nahh, that won''t work. For migration you need the same volumes, i.e. > the simplest is to use NFS or GFS, but you definitely need network > file systems for migration to really work. >Is it recommended to use GFS on a shared SAN LUN, or CLVM ? Or GFS on top of CLVM volume? I think plain CLVM should be fastest.. and obviously LVM volumes for domU disks. Any other things to take in account when choosing storage method for live migrations.. any problems with online resizing of the filesystem and/or VG? Thanks! -- Pasi