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1610 discussions

Re: [CentOS-virt] [CentOS] Very unresponsive, sometimes stalling domU (5.4, x86_64)
by Pasi Kärkkäinen 02 Mar '10

02 Mar '10

On Tue, Mar 02, 2010 at 09:30:50AM +0100, Timo Schoeler wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi list, > > please forgive cross posting, but I cannot specify the problem enough to > say whether list it fits perfectly, so I'll ask on both. > > I have some machines based with following specs (see at the end of the > email). > > They run CentOS 5.4 x86_64 with the latest patches applied, Xen-enabled > and should host one or more domUs. I put the domUs' storage on LVM, as I > learnt ages ago (what never caused any problems) and is way faster than > using file-based 'images'. > > However, there's something special about these machines: They have the > new WD EARS series drives, which use 4K sector sizes. So, I booted a > rescue system and used fdisk to start at sector 64 instead of 63 (long > story made short: Due to overhead causing the drive to do much more, > inefficient writes when starting at sector 63, the performance > collapses; with 'normal' geometry (sector 63), the drive achieves about > 25MiByte/sec writes, with starting at sector 64 partition, it achieves > almost 100MiByte/sec writes): > > [root@server2 ~]# fdisk -ul /dev/sda > > Disk /dev/sda: 1000.2 GB, 1000204886016 bytes > 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors > Units = sectors of 1 * 512 = 512 bytes > > Device Boot Start End Blocks Id System > /dev/sda1 * 64 2097223 1048580 fd Linux raid > autodetect > Partition 1 does not end on cylinder boundary. > /dev/sda2 2097224 18876487 8389632 82 Linux swap / Solaris > /dev/sda3 18876488 1953525167 967324340 fd Linux raid > autodetect > > On top of those (two per machine) WD EARS HDs there's ``md'' providing > two RAID1, /boot and LVM, as well as swap per HD (i.e. non-RAIDed). LVM > provides the / partition as well as LVs for Xen domUs. > > I have about 60 machines running that style and never had any problems. > They run like a charm. On these machines, however, domUs are *very* > slow, have a steady (!) load of about two -- 50% stating in 'wait' -- > and all operations take ages, e.g. a ``yum update'' with the recently > released updates. > > Now, can that be due to 4K issues I didn't see, nestet now in LVM? > > Help is very appreciated. > Maybe the default LVM alignment is wrong for these drives.. did you check/verify that? See: http://thunk.org/tytso/blog/2009/02/20/aligning-filesystems-to-an-ssds-eras… Especially the "--metadatasize" option. -- Pasi

2 1

Sound and VGA resolution for KVM guests
by carlopmart 26 Feb '10

26 Feb '10

Hi all, Recentlly, I have installed a Windows 7 Enterprise kvm guest under a CentOS 5.4 kvm host (fully updated) using virtio drivers and all works ok except two things: sound and vga resolution. a) How can I increase vga resolution to 1440x900 or is not possible to configure more than 1024x768 when virt-manager is used?? b) I have assigned a sound device to this windows guest (ac97) but it doesn't works. Do I need to download this driver from some location?? Under hardware view windows shows me a multimedia device but without driver installed. Thanks. -- CL Martinez carlopmart {at} gmail {d0t} com

2 1

moving from Xen to KVM
by Dave Augustus 26 Feb '10

26 Feb '10

Hello All, I have been building a new server to deploy using Xen. However, seeing that Redhat is moving towards KVM, it would seem beneficial to deply this server using KVM as well. This is a Centos 5.4 x86_64 fresh install. So here is the scoop: * running the xen kernel with 2 vms works great. I have 2 vms- a cobbler host and an ldap host. * running with non-xen kernel, I can't seem to get anything to work right. Using virt-install from the command line, I get the response of "Host does not support any virtualization options" yet I know it does. What am I missing here? I spent some hours last night searching and came up empty. Thanks in advance, Dave

5 7

guest management: 1 and only 1 instance
by Christopher Hunt 26 Feb '10

26 Feb '10

Gang, I run several KVM host machines. Due to updates, maintenance, and unexpected reboots sometime host machines are restarted. I can easily envision a scenario where HostX needs some critical packages updated or is acting up. I migrate guest0, guest1, guest2 etc. from HostX to HostY. Then, in either a planned (i.e. scheduled maintenance) or unplanned (i.e. unplanned reboot) event reboots HostX. Unfortunately guest0, guest1 and guest2 are all set to autostart on HostX but they're currently running on HostY when HostX boots.... etc etc etc Is anyone using effective packages, scripts or techniques which help maintain that all guest are running once and only once across a cluster of KVM hosts? I have been using virt-manager but it's not automated so much... Thanks for your feedback, Chris

2 1

what's wrong with using the qemu monitor with kvm/libvirt?
by Mr. X 26 Feb '10

26 Feb '10

List, http://www.redhat.com/archives/libvirt-users/2010-January/msg00012.html As in the above post, I wondered why the Qemu Monitor is not available when using kvm with libvirt. With the amount of features that are already exposed in Qemu, it might be easier to run qemu-kvm commands manually/script and forget libvirt in order to not lose this ability. -- Mark

1 0

Re: [CentOS-virt] Mounting LVM contained ntfs systems.
by Christopher G. Stach II 25 Feb '10

25 Feb '10

----- "Ben M." <centos(a)rivint.com> wrote: > I dd'd the LV from a snapshot to an empty LV on a different VG with > identical extents like this: > > dd if=/dev/vgsnapshotsource/win2k8-snapshot > of=/dev/vgtarget/win2k8-target > > I'm a little confused by what you mean by "partition" and disk in this > context. There is the LV container created, a partition, but also a > volume and presented as a "disk" to the Windows vm. I meant from the perspective of Linux. It is unclear to me how many layers are involved and whether or not you already did the kpartx bit, but if in case you didn't... If Windows is using the LV as an entire disk and partitions it, you have to use that partition table, too. -- Christopher G. Stach II http://ldsys.net/~cgs/

2 1

OpenNode (CentOS based) virtualization solution preview released
by Andres Toomsalu 25 Feb '10

25 Feb '10

Hi, We have released first preview release of OpenNode - http://opennode.activesys.org - an open source server virtualization solution providing easy to use (CentOS based) bare-metal ISO installer and supporting both OpenVZ container-based virtualization and KVM full virtualization technology on the same physical host out-of-the-box. So everybody who wants to use OpenVZ and KVM together on CentOS host this should be appealing. OpenNode main features are: 1) easy to use automated disk partitioning and LVM setup (also creating softraid setup if desired - thou true hardware raid is reccomended for production servers) 2) installs minimum set of packages needed for out-of-the-box openvz and kvm hypervisors support - together with the libvirt (inluding virsh and virt-install CLI utilities) and func (Fedora Unified Network Controller) management interfaces 3) includes stable RHEL5 2.6.18 series kernel provided by OpenVZ project and rebuilded KVM kernel module package for this ovzkernel 4) does automatic bridge networking setup needed for OpenVZ veth (which enables broadcast traffic for container) and KVM networking - you just enter interface configuration data in the installer networking screen and bridge setup is taken care of by the installer 5) includes opennode cli utility which will run at console logon - provides (currently only openvz) templates download (CentOS, Ubuntu, LTSP, OpenVPN, Bind, etc.) and registering OpenNode with central management solution (in development) 6) disables unneeded services - just run only things that are needed by hardware node to provide stable virtualization platform OpenNode installer ISO download is provided through sourceforge.net project page - http://sourceforge.net/projects/opennode Please test the installer and also give us feedback for improving OpenNode. Best regards, -- ---------------------------------------------- Andres Toomsalu, andres(a)active.ee

2 2

Moving vmware guests to a CentOS KVM server
by carlopmart 24 Feb '10

24 Feb '10

Hi all, I need to move ten CentOS/RHEL 5.4 vmware guests from a vmware ESXi 4 host to a CentOS 5.4 KVM host (fully patched). But I have two doubts. First: all these guests have two e1000 network drivers defined as a eth0,eth1 and modprobe.conf file is the same on all: alias eth0 e1000 alias eth1 e1000 alias net-pf-10 off options ipv6 disable=1 Can I change e1000 driver to virtio_net driver without problems and then update kernel??? Second doubt: all MAC address are defined with vmware range (00:50:56:XX:XX:XX) and I have configured all with HWADDR option under ifcfg-ethX files. Do I need to change all MAC address to KVM range or can I keep vmware range?? I don't need to convert virtual disks because all these guests are installed on an iSCSI luns under Solaris/ZFS servers ... Many thanks. -- CL Martinez carlopmart {at} gmail {d0t} com

4 6

Boot delay and startup order for KVM guests
by carlopmart 23 Feb '10

23 Feb '10

Hi all, Finally, I have migrated my rhel/centos guests from vmware to kvm server using virtio drivers without problems. But I need to startup these guests using certain order and assign boot delays. How can I do this?? Does kvm provides some type of tool to do it?? Or do I need to create virsh scripts to do it?? I have tried autostart option from libvirt but starts all guests at the same time. Thanks. -- CL Martinez carlopmart {at} gmail {d0t} com

3 4

Dynamically add virtio storage to guests via libvirt and KVM?
by Steven Ellis 22 Feb '10

22 Feb '10

Is this actually possible with KVM on Centos 5.4? I'd like to be able to grow the storage of a virtualised database server as required. Both the base server and virtual guest are running Centos 5.4 I've tried adding the storage but it doesn't appear until reboot. I can't force a scsi device scan as there are no entries under /sys/class/scsi_* Any ideas? Steve

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