Hi, I just started testing XEN on centos 5.3 host. I would like to know the preferable practice to store domu partitions. Currently I have one hard drive only, so I made 2 volume groups, one for the host OS and the other one (i.e. xen_vg) for domu. I wanted to make 5 domu instances, so I made 10 logical volumes -5 root (1G each) and 5 swap (256 MB each). I assigned each domu a root and swap partitions, and used yum and rpm to populate the partitions. For my current setup, is this the best scenario? I am thinking of adding a new hard dive for domu only, but I read somewhere that having the swap partitions on a separate hard drive is better, would you comment on this please? I’ve had some messages during the boot time (4gb seg fixup...) and to remove them I was told to remove the tls libs, but I noticed that tls is already empty, so I am curious if this indicates improper installation of the domu instances? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, Jun 22, 2009 at 8:52 PM, fmb fmb<feedmb@googlemail.com> wrote:> Hi, > > I just started testing XEN on centos 5.3 host. I would like to know the > preferable practice to store domu partitions. Currently I have one hard > drive only, so I made 2 volume groups, one for the host OS and the other one > (i.e. xen_vg) for domu. I wanted to make 5 domu instances, so I made 10 > logical volumes -5 root (1G each) and 5 swap (256 MB each). I assigned each > domu a root and swap partitions, and used yum and rpm to populate the > partitions.Using yum and rpm to create domU is actually quite advanced setup. Are you sure you just started using Xen? :D Don''t forget postinstall stuff, like system-config-authentication to (at least) enable shadow and md5 passwords.> > For my current setup, is this the best scenario?It''s a generic setup that should work well on most cases. 1GB for root is bit cramped though, as logs can fill up space quite easily.> > I am thinking of adding a new hard dive for domu only, but I read somewhere > that having the swap partitions on a separate hard drive is better, would > you comment on this please?It''s usually desirable to split OS disk from application and data. As for swap, putting it on separate disk would minimize the effect of rogue domU swapping heavily (possibly because lack of memory, common on hosting environment). IMHO a well-designed system should not utilize swap as it can be performance killer.> > I’ve had some messages during the boot time (4gb seg fixup...) and to remove > them I was told to remove the tls libs, but I noticed that tls is already > empty, so I am curious if this indicates improper installation of the domu > instances?I haven''t use 32bit domU in a long time, so I could be wrong, but kernel-xen RPM should have /etc/ld.so.conf.d/kernelcap*.conf that contains hwcap 0 nosegneg IMHO it''s easier to simply use 64bit dom0 and domU. -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> From: xen-users-bounces@lists.xensource.com[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of fmb fmb> Sent: Monday, June 22, 2009 9:53 AM > To: xen-users@lists.xensource.com > Subject: [Xen-users] New xen user, basic inquiries> I wanted to make 5 domu instances, so I made 10 logical volumes -5root (1G each) and 5 swap (256 MB each). Our setup is very similar to yours. We''ve been running with it for about two years, and find the one-logical-volume-per-domu-filesystem approach very flexible and practical (as long as you don''t need HVM guests). Resizing a volume is easy.> For my current setup, is this the best scenario?"Best" depends on your needs. The main downside here is that you can''t use the CentOS installer out of the box. But you''ve already figured out how to work around it. Are you using pygrub to boot, or do you boot from a kernel/ramdisk that live outside the domU filesystem?> I am thinking of adding a new hard dive for domu only, but I readsomewhere that having the swap partitions> on a separate hard drive is better, would you comment on this please?Truthfully, most of our domU instances don''t have any swap configured. Even if we have it, it''s only a safety net to buy some time before the OOM killer destroys a runaway process, so top performance from swap isn''t really a consideration. RAM is cheap and plentiful nowadays. Alternatively, you can always create a swap file if you prefer not to create a dedicated swap volume.> Ive had some messages during the boot time (4gb seg fixup...) and toremove them I was told to remove the> tls libs, but I noticed that tls is already empty, so I am curious ifthis indicates improper installation of the domu> instances?As already alluded to on this thread, a 64-bit kernel is superior to a 32-bit kernel. With a bit of care, you can even boot and run a 32-bit distro from a 64-bit kernel, so there''s little reason to suffer with the tls workaround unless you have ancient hardware that isn''t 64-bit capable. -Jeff _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi, Thnx for the quick help. I appreciate it. Regarding the post install, i chroot to the domu and make the basic configurations. thnx for that shadow and md5 hint... 1GB for the root since i am only testing, so i think having all domu lvms in one vg is normal.. On Mon, Jun 22, 2009 at 5:13 PM, Fajar A. Nugraha <fajar@fajar.net> wrote:> > I haven''t use 32bit domU in a long time, so I could be wrong, but > kernel-xen RPM should have /etc/ld.so.conf.d/kernelcap*.conf that > contains > > hwcap 0 nosegneg > > IMHO it''s easier to simply use 64bit dom0 and domU.Thnx, I did that and the messages disappeared... _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, Jun 22, 2009 at 6:23 PM, Jeff Sturm <jeff.sturm@eprize.com> wrote:> > Are you using pygrub to boot, or do you boot from a kernel/ramdisk that > live outside the domU filesystem?I am using the host kernel, and i made a ramdisk w/o scsi modules to prevent kernel panic. Do u prefer pygrub?> Truthfully, most of our domU instances don''t have any swap configured. > Even if we have it, it''s only a safety net to buy some time before the > OOM killer destroys a runaway process, so top performance from swap > isn''t really a consideration. RAM is cheap and plentiful nowadays. > Alternatively, you can always create a swap file if you prefer not to > create a dedicated swap volume.So you just assign enough RAM and forget about the swap....> As already alluded to on this thread, a 64-bit kernel is superior to a > 32-bit kernel. With a bit of care, you can even boot and run a 32-bit > distro from a 64-bit kernel, so there''s little reason to suffer with the > tls workaround unless you have ancient hardware that isn''t 64-bit > capable. > -Jeff >Thnx to fajr the cure was in his reply. i think i might consider 64bit... _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> From: fmb fmb [mailto:feedmb@googlemail.com] > Sent: Monday, June 22, 2009 11:47 AM > To: Jeff Sturm > Cc: xen-users@lists.xensource.com > Subject: Re: [Xen-users] New xen user, basic inquiries> I am using the host kernel, and i made a ramdisk w/o scsi modules toprevent kernel panic. Do u> prefer pygrub?No, I was just curious. I''ve used pygrub before, but the current lot of virtual machines we''ve deployed don''t use it. The upside of specifying kernel/ramdisk in our domU configs is that I have one place to install kernel updates. The downside is that the distro tools (rpm, yum) don''t know about it, and the kernel modules installed on a domU can become out of date with the kernel if we don''t update all at once. When that happens, it''s not disastrous, because our ramdisk image already contains all the modules we need. But we do get a few boot-time warnings. Overall I like being able to supply all modules in a ramdisk (or even in the kernel image, in which case the ramdisk becomes optional) but it does feel like I''m fighting with the distro at times, as the distro wants to behave in another way. After years of Xen/VMWare, we''re still learning and just scratching the surface of how we can take full advantage of virtualization, or so it seems. -Jeff _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users