I''m new to xen, and I must say that so far it''s the coolest thing since sliced bread. I have a kind of naive question... Running CentOS on both the host and guest, it was easy to use virt-install to get everything going. Now, I want to clone my machine, mount it with " -o loop" and modify the setup before bringing it online. I used virt-clone to make the machine, but when I try to mount it, mount complains that it needs a filesystem type. I assume that I''ve missed a step to make an image of the new machine. Thanks for any help. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Sat, Dec 20, 2008 at 11:43 AM, <maillists0@gmail.com> wrote:> I''m new to xen, and I must say that so far it''s the coolest thing since > sliced bread. I have a kind of naive question... > > Running CentOS on both the host and guest, it was easy to use virt-install > to get everything going. Now, I want to clone my machine, mount it with " -o > loop" and modify the setup before bringing it online. I used virt-clone to > make the machine, but when I try to mount it, mount complains that it needs > a filesystem type. I assume that I''ve missed a step to make an image of the > new machine. Thanks for any help. >This should give you the pieces you are missing: (kpartx is your friend here) http://www.centos.org/docs/5/html/Virtualization-en-US/ch-virt-accessing-data.html Cheers, Todd -- Todd Deshane http://todddeshane.net http://runningxen.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Sat, Dec 20, 2008 at 4:37 PM, <maillists0@gmail.com> wrote:> > > >> >> This should give you the pieces you are missing: >> (kpartx is your friend here) >> >> http://www.centos.org/docs/5/html/Virtualization-en-US/ch-virt-accessing-data.html> Thanks! I have a question. I''m not sure what to use for "guest1" in this > line: kpartx -av /dev/xen/guest1. In /dev/xen on my system, I have this list > of devices: > > blktap0 blktap1 evtchn tapctrlread1 tapctrlwrite1 > > How do I know which one my guest is using?Those instruction assume that you are working with logical volumes. The kpartx should be applied to the disk image file, whatever that may be. That will then make the partitions available in /dev/mapper. If you are working with LVs either as the disk or on the disk, then the standard LVM commands apply. Hope that helps. Cheers, Todd -- Todd Deshane http://todddeshane.net http://runningxen.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Sat, Dec 20, 2008 at 4:40 PM, Todd Deshane <deshantm@gmail.com> wrote:> On Sat, Dec 20, 2008 at 4:37 PM, <maillists0@gmail.com> wrote: > > > > > > > >> > >> This should give you the pieces you are missing: > >> (kpartx is your friend here) > >> > >> > http://www.centos.org/docs/5/html/Virtualization-en-US/ch-virt-accessing-data.html > > > Thanks! I have a question. I''m not sure what to use for "guest1" in this > > line: kpartx -av /dev/xen/guest1. In /dev/xen on my system, I have this > list > > of devices: > > > > blktap0 blktap1 evtchn tapctrlread1 tapctrlwrite1 > > > > How do I know which one my guest is using? > > Those instruction assume that you are working with logical volumes. > The kpartx should be applied to the disk image file, whatever that > may be. That will then make the partitions available in /dev/mapper. > If you are working with LVs either as the disk or on the disk, then > the standard LVM commands apply. > > > Hope that helps. > > Cheers, > Todd > > -- > Todd Deshane > http://todddeshane.net > http://runningxen.com >I figured that''s what was going on. When I try to use kpartx -av (or -lv for a dry run) against the files I''m using as disk images though, I get a simple "failed to stat() filename" message. The machines start just fine, though, and I can manually stat them. No _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Sat, Dec 20, 2008 at 5:25 PM, <maillists0@gmail.com> wrote:> I figured that''s what was going on. When I try to use kpartx -av (or -lv for > a dry run) against the files I''m using as disk images though, I get a simple > "failed to stat() filename" message. The machines start just fine, though, > and I can manually stat them. No >Maybe this bug/patch could be helpful: http://bugs.centos.org/view.php?id=2882 Cheers, Todd -- Todd Deshane http://todddeshane.net http://runningxen.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Sat, Dec 20, 2008 at 5:52 PM, Todd Deshane <deshantm@gmail.com> wrote:> On Sat, Dec 20, 2008 at 5:25 PM, <maillists0@gmail.com> wrote: > > I figured that''s what was going on. When I try to use kpartx -av (or -lv > for > > a dry run) against the files I''m using as disk images though, I get a > simple > > "failed to stat() filename" message. The machines start just fine, > though, > > and I can manually stat them. No > > > > Maybe this bug/patch could be helpful: > http://bugs.centos.org/view.php?id=2882 > > Cheers, > Todd > > -- > Todd Deshane > http://todddeshane.net > http://runningxen.com >Thank you! Apologies, I really should have googled that first. I just assumed that I had done something wrong. While we''re on this subject, I could use an opinion about something. I''d like to use a xen machine as a production database. The plan would be to run only one guest and give it most of the system resources. I read that disk partitions give better performance than files, which makes sense, but it also appears easier to clone and use files than partitions, and administration and maintainance time is certainly an issue. So the question is this: in this circumstance, with the entire machien dedicated to one guest, do you think that the performance difference is enough to warrant the use of a dedicated partition? How substantial is it? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> While we''re on this subject, I could use an opinion about something. I''d > like to use a xen machine as a production database. The plan would be to run > only one guest and give it most of the system resources. I read that disk > partitions give better performance than files, which makes sense, but it > also appears easier to clone and use files than partitions, and > administration and maintainance time is certainly an issue. So the question > is this: in this circumstance, with the entire machien dedicated to one > guest, do you think that the performance difference is enough to warrant the > use of a dedicated partition? How substantial is it? >This is actually a popular question: http://xen.markmail.org/message/yjjjhl2qr4hjvdom?q=file+partition+performance#query:file%20partition%20performance+page:1+mid:cdhlcfyfzzjpey2y+state:results http://xen.markmail.org/message/v6wus56oes3uwu5t?q=file+partition+performance#query:file%20partition%20performance+page:1+mid:y3tim7urxsfiwray+state:results http://xen.markmail.org/message/kgr4v4iitkaszlh4?q=file+partition+performance&page=2#query:file%20partition%20performance+page:2+mid:hrr66tw37ifleznc+state:results Some basics to keep in mind. Best thing to do if you are worried about it run some benchmarks (iozone is a good one). Keep in mind the workload that you want to run With a network storage server, or even file server, you can get the best of both (but then you move a potential bottleneck to the network) You should test as much as you can and ask for help/opinions if you get strange results. Hope that helps. Cheers, Todd P.S. you said you are new to Xen, do you have the Running Xen book? -- Todd Deshane http://todddeshane.net http://runningxen.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users