Lippert, Kenneth B.
2010-Jun-28 19:48 UTC
[Xen-users] Verify my understanding of PVs mounting partitions please
I haven''t been able to test this on my hardware yet, but as I understand this should be possible: I have a computer with several physical partitions: (say /dev/sda1. /dev/sdb1, /dev/sdb2). I build a PV which boots from a file-based disk image somewhere in the /dev/sdb1 partition (/usr1/xen_vm_images/disk0).>From that PV I can mount one of the real physical partitions (/dev/sdb2)and read/write to it. I can also export it via NFS.>From the dom0 I can ALSO mount /dev/sdb2 (being careful not to write toit). I want to do this so that I can backup up the data in /dev/sdb2 from the dom0 to a totally different machine without using time/resources on the PV. On the second backup machine, I also have a /dev/sdb2 partition, which receives the backups. I also periodically, manually copy the disk image of the PV to the backup machine (because I cannot run Remus on SuSE 10.1). I want to be able to stop the PV on the primary, and start it up on the backup machine. Does this make sense? Note that the /dev/sdb2 partition may be very large, several terabytes, but the PV disk image is smaller, maybe 80GB. Thank you in advance for any direction. -k Kenn Lippert Computation & Simulation Modeling, Product Manufacturing Division Alcoa Technical Center. Tel: 724-337-2691 Email: kenneth.lippert@alcoa.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
John Haxby
2010-Jun-29 11:16 UTC
Re: [Xen-users] Verify my understanding of PVs mounting partitions please
On 28/06/10 20:48, Lippert, Kenneth B. wrote:> I haven''t been able to test this on my hardware yet, but as I understand > this should be possible: > > I have a computer with several physical partitions: (say /dev/sda1. > /dev/sdb1, /dev/sdb2). > > I build a PV which boots from a file-based disk image somewhere in the > /dev/sdb1 partition (/usr1/xen_vm_images/disk0). > > > From that PV I can mount one of the real physical partitions (/dev/sdb2) > and read/write to it. I can also export it via NFS. > > > From the dom0 I can ALSO mount /dev/sdb2 (being careful not to write to > it). >No; no more than you can share a disk between two machines; the file system visible through the read-only mount is dirty, inconsistent and changing in ways that read-only file systems are not able to change. If you want access to the same file system from more than one machine (real or virtual) then you need a clustered file system. jch _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users