Can anybody tell me if it makes a difference if domU''s have separate LVM volume groups? For instance, the Xen User Manual ( http://tx.downloads.xensource.com/downloads/docs/user/#SECTION03330000000000000000) says, when setting up a domU''s disks with LVM, to do a vgcreate vg /dev/sda10 Should each domU have it''s own volume group, or can all the domU''s share the ''vg'' volume group? TIA, Rich ______________________________________ Richard Yumul rmy@sdtechnix.com http://www.sdtechnix.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Rich Yumul wrote:> Can anybody tell me if it makes a difference if domU''s have separate LVM > volume groups? > > For instance, the Xen User Manual ( > http://tx.downloads.xensource.com/downloads/docs/user/#SECTION03330000000000000000) > says, when setting up a domU''s disks with LVM, to do a > > vgcreate vg /dev/sda10 > > Should each domU have it''s own volume group, or can all the domU''s share > the ''vg'' volume group?It''s related to LVM, not to Xen. You can create several logical volumes (lvcreate) in a volume group. These volumes will be "shown" as normal devices in /dev/vg/. Each DomU can then be attached to one (or several, depending on the number of "disks" your DomU is attached to) logical volume of the same volume group: lcslis-dom0:~# lvscan ACTIVE ''/dev/vg1/slis-part1'' [8,00 GB] inherit ACTIVE ''/dev/vg1/slis-part3'' [1,00 GB] inherit ACTIVE ''/dev/vg1/slis-swap'' [512,00 MB] inherit ACTIVE ''/dev/vg1/lcs-part1'' [8,00 GB] inherit ACTIVE ''/dev/vg1/lcs-swap'' [512,00 MB] inherit ACTIVE ''/dev/vg1/debian-swap'' [512,00 MB] inherit ACTIVE ''/dev/vg1/slis-part2'' [10,25 GB] inherit ACTIVE ''/dev/vg1/lcs-part2'' [10,25 GB] inherit ACTIVE ''/dev/vg1/lcs-part3'' [10,25 GB] inherit ACTIVE ''/dev/vg1/debian-part1'' [10,25 GB] inherit I have there 3 DomUs running on: slis, lcs and debian. HTH -- Olivier Le Cam Département des Technologies de l''Information et de la Communication CRDP de l''académie de Versailles _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Thanks for your reply - What I really want to know is that if each virtual machine should be on it''s own volume group, or if it''s ok if all the domU''s share the same volume group? Or does it even make a difference? Thanks! Rich On Thu, 2006-12-07 at 00:56 +0100, Olivier Le Cam wrote:> Rich Yumul wrote: > > Can anybody tell me if it makes a difference if domU''s have separate LVM > > volume groups? > > > > For instance, the Xen User Manual ( > > http://tx.downloads.xensource.com/downloads/docs/user/#SECTION03330000000000000000) > > says, when setting up a domU''s disks with LVM, to do a > > > > vgcreate vg /dev/sda10 > > > > Should each domU have it''s own volume group, or can all the domU''s share > > the ''vg'' volume group? > > It''s related to LVM, not to Xen. You can create several logical volumes > (lvcreate) in a volume group. These volumes will be "shown" as normal > devices in /dev/vg/. > > Each DomU can then be attached to one (or several, depending on the > number of "disks" your DomU is attached to) logical volume of the same > volume group: > > lcslis-dom0:~# lvscan > ACTIVE ''/dev/vg1/slis-part1'' [8,00 GB] inherit > ACTIVE ''/dev/vg1/slis-part3'' [1,00 GB] inherit > ACTIVE ''/dev/vg1/slis-swap'' [512,00 MB] inherit > ACTIVE ''/dev/vg1/lcs-part1'' [8,00 GB] inherit > ACTIVE ''/dev/vg1/lcs-swap'' [512,00 MB] inherit > ACTIVE ''/dev/vg1/debian-swap'' [512,00 MB] inherit > ACTIVE ''/dev/vg1/slis-part2'' [10,25 GB] inherit > ACTIVE ''/dev/vg1/lcs-part2'' [10,25 GB] inherit > ACTIVE ''/dev/vg1/lcs-part3'' [10,25 GB] inherit > ACTIVE ''/dev/vg1/debian-part1'' [10,25 GB] inherit > > I have there 3 DomUs running on: slis, lcs and debian. > > HTH >______________________________________ Richard Yumul rmy@sdtechnix.com http://www.sdtechnix.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Rich Yumul wrote:> Thanks for your reply - What I really want to know is that if each > virtual machine should be on it''s own volume group, or if it''s ok if all > the domU''s share the same volume group? Or does it even make a difference? > > Thanks! > > RichThey can share one, but you will want to use CLVM if you don''t want to screw everything up for yourself. This will also soften the blow of moving to shared storage if/when you get more Xen hosts. -- Christopher G. Stach II _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 6 Dec 2006 at 14:27, Rich Yumul wrote:> Can anybody tell me if it makes a difference if domU''s have separate LVM > volume groups? > > For instance, the Xen User Manual > ( http://tx.downloads.xensource.com/downloads/docs/user/#SECTION03330000000000000000) says, when setting up a domU''s disks with LVM, to do a > > vgcreate vg /dev/sda10 > > Should each domU have it''s own volume group, or can all the domU''s share > the ''vg'' volume group?Hi! My little experience on performance indicates that booting two or more DomUs (SLES10) in parallel drives a two disk RAID1 to its limits with different LVs on the RAID. So if you have more disks, I''d suggest to distribute DomUs there. Partitions, VGs, and LVs are just a higher level of managing storage space. Regards, Ulrich _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi, It depends what do you mean by "all" domU! How many? We have been using single volume group for atleast 3-4 domU''s and never had a problem! Regards Omer On 12/7/06, Christopher G. Stach II <cgs@ldsys.net> wrote:> > Rich Yumul wrote: > > Thanks for your reply - What I really want to know is that if each > > virtual machine should be on it''s own volume group, or if it''s ok if all > > the domU''s share the same volume group? Or does it even make a > difference? > > > > Thanks! > > > > Rich > > They can share one, but you will want to use CLVM if you don''t want to > screw everything up for yourself. This will also soften the blow of > moving to shared storage if/when you get more Xen hosts. > > -- > Christopher G. Stach II > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >-- --------------------------------------------------------------- CERN – European Organization for Nuclear Research Information Technology Department CH-1211 Geneva 23 Phone: +41 (0) 22 767 7996 Fax: +41 (0) 22 767 4900 E-mail : Omer.Khalid@cern.ch Homepage: http://cern.ch/Omer.Khalid _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users