Pallab Chakrabarty wrote:>Kindly input as how to go ahead with unionfs with xen integration..You might get a response if you give some clue as to your requirements. What are you trying to achieve ? What exactly do you mean by "integration" ? -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Pallab Chakrabarty wrote:>I want to use unionfs system as xen storage.. > >However couldnt find any detail procedure to do "UnionFS in Xen by >initrd"..That''s still not very useful ! Are you trying to have a common filesystem image shared by many DomUs, and use unionfs to allow each DomU to have it''s own modified version ? Are you hoping to do this in Dom0 and export the filesystem to the DomUs ? Or are you hoping to export the common filesystem (readonly) and run unionfs in the DomU ? Or something different ? -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Pallab Chakrabarty wrote:>>Are you trying to have a common filesystem image >>shared by many DomUs, and use unionfs to allow >>each DomU to have it''s own modified version ?>YES > >kindly guide me..I don''t know - not something I''ve ever worked with. A quick look in the Xen manual (http://tx.downloads.xensource.com/downloads/docs/user/) comes up with this :>Block devices should typically only be shared between domains in a >read-only fashion otherwise the Linux kernel''s file systems will get >very confused as the file system structure may change underneath >them (having the same ext3 partition mounted rw twice is a sure fire >way to cause irreparable damage)! Xend will attempt to prevent you >from doing this by checking that the device is not mounted >read-write in domain 0, and hasn''t already been exported read-write >to another domain.Now, if you are prepared to do the unionfs stuff in the DomU then I''d guess you could export the shared block device read-only to each guest, plus a separate read-write volume per guest to union with it. Looking at the live CD systems (like Knoppix) might give you some ideas. -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> Pallab Chakrabarty wrote: > >>> Are you trying to have a common filesystem image >>> shared by many DomUs, and use unionfs to allow >>> each DomU to have it''s own modified version ? > >> YES >>> Now, if you are prepared to do the unionfs stuff in the DomU then I''d guess > you could export the shared block device read-only to each guest, plus a > separate read-write volume per guest to union with it.You didn''t mention what your primary goal is. If your goal is to save space, then IMHO it''s not worthed. One, as Simon mentioned, you need to do union in domU. That means modifying domU. Too much effort for a general purpose domU. Unless of course if your goal is to create something like Live CD where unionfs features is essentional, and performance doesn''t really matter. Two, an easier approach (as in you don''t need to have a special domU) to save space would be to use tap:qcow, LVM snapshot, or zfs-backed zvol. All three has their own advantage and limitations. If your goal is testing purposes for Linux PV domUs, qcow would be easiest. Regards, Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users