Re: [CentOS-virt] Resizing EXT3 partition in guest instance CentOS5
2011/2/6 Poh Yong Hwang yong...@gmail.com: Hi, I have an issue. I have already resize the partition using Gparted. Now how can i resize the actual image size in virtual manager? I do not see any option for me to change the size of the allocated hard disk. You're probably looking for the resize feature of the qemu-img command, I'm fairly sure that virt-manager doesn't do resizing: man qemu-img Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Resizing EXT3 partition in guest instance CentOS5
2011/2/6 Poh Yong Hwang yong...@gmail.com: Hi Kenni, Sorry i might have miss it but if i do a man of qemu-img, i do not see resize option. I only see create, convert, commit and info. Ohh, I'm sorry then :( Guess the qemu-img version in CentOS 5 just is too old... qemu-img *is* the tool you want, nevertheless...you might want to use another system with a newer version of qemu-img to do the resizing or manually compiling a newer version of qemu-kvm on your current system (to avoid conflicts with the installed qemu-kvm version). Otherwise you'll have to use another approach, like the one compdoc proposed. Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Resizing EXT3 partition in guest instance CentOS5
2011/2/6 Thomas Smith theitsm...@gmail.com: I am coming into this discussion a little late, so apologies if I ask for any information previously provided. I can help you with this, but I'll need to know the domU's file system layout to do so. Can you send the output of the following commands? * fdisk -l * mount * df -h And if you're using LVM: * vgdisplay * lvdisplay KVM not Xen according to original post - and the partition in the guest has already been resized with gparted, so no reason to perform any more actions within the guest - only thing missing is to resize the qemu image on the host (I assume the OP is using regular file-based images in virt-manager as nothing has been mentioned about this, eg. not iSCSI, NFS, LVM, etc.). Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] [HOWTO] Running Xen 4.0 host (dom0) with Redhat Enterprise Linux 6 (RHEL6)
2010/11/18 Pasi Kärkkäinen pa...@iki.fi: Hello, If you're interested in running Xen 4.0 hypervisor/dom0 on RHEL6, take a look at here: http://wiki.xen.org/xenwiki/RHEL6Xen4Tutorial It explains steps needed to rebuild Xen 4.0.1 src.rpm from Fedora on RHEL6, and how to fetch dom0 capable 2.6.32.x kernel from upstream git repository. It also shows how to get libvirt/virt-manager working with Xen on RHEL6. Hopefully it helps :) Very nice, thanks! I'll test it when time permits, but for now I'll enjoy the working-out-of-the-box experience I get with KVM on RHEL ;) Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] what scheduling algorithm does KVM use?
2010/11/19 Nick oinksoc...@letterboxes.org: The problem with this is that it is obviously more of a constraint to have two physical CPUs available. Therefore adding virtual CPUs to a co-scheduled VM can actually make performance worse if the physical CPUs are under any sort of contention. Performance degrades rapidly under load - which is exactly what you don't want for a webserver. Therefore advice seems to be to avoid using multi-virtual CPU VMs. [1] As long as you keep the number of CPUs for *each* VM - equal to or lower than - the number of physical cores, your performance should not suffer with KVM. If you assign more CPUs to one VM than you have available cores (a core can also be a hyperthreaded core), you will for sure run into performance problems. I did try and research the algorithm(s) used by KVM. Apparently it doesn't use co-scheduling, but possibly something called the completely fair scheduler, The good thing about KVM compared to other virtualization solutions, is that KVM doesn't try to reinvent the wheel. It leaves scheduling to the Linux kernel, so whatever your Linux system is setup to use, KVM will use that. You can choose to run CFS (Completely Fair Scheduler), deadline, BFS, or whatever scheduler you prefer. As long as Linux uses it, KVM will use it. but I'm no an expert in VM scheduling and I didn't manage to discover what this means, nor specifically what the implications are for performance were in terms of scaling up the number of virtual CPUs on KVM. (I understand that the number of virtual CPUs supported by KVM is be quite high.) If you want a really competent answer to your question, send it to the kvm-devel list...they don't mind user questions like this, and as long as you're asking a relevant question, there's a good chance of getting a highly competent answer :) Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] What are KVM guest cores?
Do you have a rule of thumb as to how many core to assign to a guest? For instance, with an Intel x5650 with 6 real and 12 hyperthreaded cores, how many cores would you assign to the guest? It fully depends on the load of your guests and how many guests you want/need to run on a single server. You need to perform some testing to know what will work the best in your case. One thing to remember though: In your case, if you create two guests with 12 virtual CPUs each, and one of them crashes and take all its 12 virtual CPUs up to 100%, it will essentially take most of the processing power away from the second guest, leaving the second guest in a close-to-useless state (depending on your scheduler, but you get the point). If you on the other hand had assigned 6 cores to each of them, the second guest would have remained unaffected, since it just uses the 6 cores with no load. So if your guest will not utilize the extra CPUs anyway, then don't assign them. Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] what scheduling algorithm does KVM use?
2010/11/19 Nick oinksoc...@letterboxes.org: Thanks for the quick reply. On 18/11/10 23:45, Kenni Lund wrote: The good thing about KVM compared to other virtualization solutions, is that KVM doesn't try to reinvent the wheel. It leaves scheduling to the Linux kernel, so whatever your Linux system is setup to use, KVM will use that. You can choose to run CFS (Completely Fair Scheduler), deadline, BFS, or whatever scheduler you prefer. As long as Linux uses it, KVM will use it. Is this process scheduling we're talking about here? Yep, a virtual CPU is just a process on the host Linux system. So, this sounds feasible... except if virtual CPUs must have time shared equally as the VMWare co-scheduling explanations imply. A scheduler for threads / processes presumably wouldn't guarantee such a thing? I think cgroups is the solution, if you want to guarantee resources to some guests. I haven't tested it with KVM, but perhaps nice and ionice can be useful as well...the guests are just Linux processes after all. Maybe I'll go and investigate the KVM list :) Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM: where are the directions?
2010/11/14 MargoAndTodd margoandt...@gmail.com: On 11/13/2010 07:44 AM, compdoc wrote: $ uname -r -m 2.6.18-194.26.1.el5 i686 $ rpm -qa \*kvm\* kvm-36-1 kmod-kvm-36-3 Not even close to 83. :-( My centos 5.5 has kvm 83. I'm not sure how you got that old stuff I am 32 bit. yum install kvm kmod-kvm You might have it installed it with yum, but in that case you've added 3rd party RPM-repositories (rpmforge, EPEL, etc). These are the packages which were available in *32 bit* CentOS 5.5 at release time (search for kvm and you'll find nothing): http://mirror.stanford.edu/yum/pub/centos/5.5/os/i386/CentOS/ And these are the packages available currently to *32bit* CentOS 5.5 through updates: http://mirror.stanford.edu/yum/pub/centos/5.5/updates/i386/RPMS/ (still nothing) Now, these are the packages which were available in *64bit* CentOS 5.5 at release time: http://mirror.stanford.edu/yum/pub/centos/5.5/os/x86_64/CentOS/ Notice that this list contains kvm-83-164.el5.x86_64.rpm and other related KVM packages... ...and the current 64-bit updates: http://mirror.stanford.edu/yum/pub/centos/5.5/updates/x86_64/RPMS/ which contains several kvm-packages, with the latest being kvm-83-164.el5_5.23.x86_64.rpm. So, as I said, the 32 bit CentOS doesn't contain KVM, not v36, not v83 - you'll need a 64-bit system. Also, if you want a stable system, DON'T use 3rd party repositories unless you take extremely care and know what you're doing. If you enable some random bleeding edge 3rd party repository, and lets yum install packages and updates from it, you could just as well setup your server with some bleeding edge Linux distribution instead of RHEL/CentOS; Fedora, Ubuntu Desktop, Gentoo, Arch Linux, [insert your favorite bleeding edge distro here]. Unless you've setup yum priorities (which is not a good thing either, but better than nothing), yum will always download the unstable packages from the 3rd party repositories, and replace stable CentOS packages with them (since they're newer). Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM: where are the directions?
2010/11/13 MargoAndTodd margoandt...@gmail.com: On 11/11/2010 01:50 PM, Kenni Lund wrote: You'll never need to run it from the command line, use the available management tools (libvirt+virsh from the command line, libvirt+virt-manager from X11), it makes your life much much easier. I've been running qemu-kvm from the command line for several years, and while it's fine to know how the system works, then you definitely don't want to manage your enterprise virtual machines that way. For example, if you start qemu-kvm twice in parallel, with the same HDD image, you'll damage or destroy your HDD image. Libvirt takes care of such banalities and many others. Thank you! These are small business servers. The CentOS server is the only server on the network. I start my VM's in rc.local and shut them down in rd.shutdown (I wrote my own). So, I am stuck with the command line. Thank you for the heads up on running them twice! But, on my new office machine, I will be running them headed, so I will be using your instructions there. Running from the command line doesn't mean you can't use the management tools: Quick'n'dirty overview: Install new guests: virt-install Start guest: virsh start $guestname List running guests: virsh list virsh list --all Shutdown guest (sends an ACPI signal to the guest, telling it to shutdown correctly - same a clicking on the power button for 1 sec on most computers): virsh shutdown $guestname Shutdown guest immediately (like pulling the power cable from a computer): virsh destroy $guestname Edit a guest: virsh edit $guestname etc. etc...run virsh --help and virt-install --help for more options. Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM: where are the directions?
2010/11/13 MargoAndTodd margoandt...@gmail.com: On 11/11/2010 01:50 PM, Kenni Lund wrote: No, you're not running an old version of qemu-kvm in CentOS. Like most other packages, Red Hat has selected an (old and stable) version as the baseline version and then backported bugfixes and new features from newer versions of the package, to fulfill the needs of their enterprise customers. kvm-83 in CentOS is NOT equal to upstream kvm-83. That said, as you've probably already read in the docs, KVM is a technology preview in RHEL 5.x...6.0 will be the first version with official/stable KVM support by Red Hat. Best regards Kenni Hi Kenni, This is my setup: $ cat /etc/redhat-release CentOS release 5.5 (Final) $ uname -r -m 2.6.18-194.26.1.el5 i686 $ rpm -qa \*kvm\* kvm-36-1 kmod-kvm-36-3 Not even close to 83. :-( These KVM-packages are from some 3rd party repository, aren't they? I don't think that 5.5 has KVM support on i686 at all...use CentOS 5.5 x86_64 instead. Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM: where are the directions?
2010/11/13 Mathieu Baudier mbaud...@argeo.org: kvm-83. That said, as you've probably already read in the docs, KVM is a technology preview in RHEL 5.x...6.0 will be the first version with official/stable KVM support by Red Hat. My understanding is that KVM was tech preview in RHEL/CentOS 5.4 and officially supported from RHEL/CentOS 5.5. Sorry, you're right...nevertheless, you still need RHEL/CentOS 6.0 to get stuff like stable ABI for Windows guests. Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM: where are the directions?
2010/11/11 MargoAndTodd margoandt...@gmail.com: On 11/10/2010 08:31 PM, Mark Pryor wrote: --- On Wed, 11/10/10, jaye...@gmail.comjaye...@gmail.com wrote: From: jaye...@gmail.comjaye...@gmail.com Subject: Re: [CentOS-virt] KVM: where are the directions? To: Discussion about the virtualization on CentOScentos-virt@centos.org Date: Wednesday, November 10, 2010, 7:15 PM rpm -ql kvm rpm -qa | grep kvm to continue this: - verify an amd64 install of kvm -- $ rpm -qa | grep kvm etherboot-zroms-kvm-5.4.4-13.el5.centos kvm-83-164.el5_5.21 kmod-kvm-83-164.el5_5.21 $ sudo lsmod | grep kvm kvm_amd 69416 0 kvm 226336 2 ksm,kvm_amd yum install bridge-utils tunctl - snip - kvm is basically qemu. The kvm launcher is (by default) not in your path: /usr/libexec/qemu-kvm request help on qemu-kvm and you will see almost the same thing which is in qemu. Trying to learn kvm via libvirt is over-kill - stick with the commandline. You'll never need to run it from the command line, use the available management tools (libvirt+virsh from the command line, libvirt+virt-manager from X11), it makes your life much much easier. I've been running qemu-kvm from the command line for several years, and while it's fine to know how the system works, then you definitely don't want to manage your enterprise virtual machines that way. For example, if you start qemu-kvm twice in parallel, with the same HDD image, you'll damage or destroy your HDD image. Libvirt takes care of such banalities and many others. Fedora 13 Live CD: qemu-kvm -cdrom ./Fedora-13-i686-Live-XFCE.iso -boot d -m 384 -net nic,model=rtl8139 -localtime -usb Froze up at automatic boot in 10 seconds. This is probably because my CentOS 5.5 is 32 bit and I am running a really old version of qemu-kvm. No, you're not running an old version of qemu-kvm in CentOS. Like most other packages, Red Hat has selected an (old and stable) version as the baseline version and then backported bugfixes and new features from newer versions of the package, to fulfill the needs of their enterprise customers. kvm-83 in CentOS is NOT equal to upstream kvm-83. That said, as you've probably already read in the docs, KVM is a technology preview in RHEL 5.x...6.0 will be the first version with official/stable KVM support by Red Hat. Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Latest KVM for 5.5...
2010/10/2 Tom Bishop bisho...@gmail.com: what I would like to know what is the latest KVM that I can run with 5.5 and Run the qemu-kvm version included with CentOS and use the KVM modules included in the default CentOS kernel - these versions are tweaked to work the best in CentOS/RHEL. what are the best management tools to use, I looked at the wiki but it also referenced the redhat doc's Use the official ones, virsh (console) and virt-manager (graphical). For documentation, use the RHEL Virtualization guide at: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Virtualization/index.html Best regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Virt-install Error on Centos 5.4 64bit and kvm
2010/7/27 cris rock quenerovi...@hotmail.com: On the /var/log/libvirt/qemu/p3k0401.log: LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin HOME=/ /usr/bin/qemu-system-x86_64 -S -M rhel5.4.0 -m 1024 -smp 1 -name p3k0401 -uuid 7658c102-0738-724c-40eb-e1c58b2c2369 -domid 3 -nographic -monitor pty -pidfile /var/run/libvirt/qemu//p3k0401.pid -no-reboot -boot c -kernel /var/lib/libvirt/boot/virtinst-vmlinuz.O_SOVo -initrd /var/lib/libvirt/boot/virtinst-initrd.img.0ba0Fp -append method=http://10.1.4.80 -drive file=//dev/VolGroup01/p3k0401logvol,if=ide,index=0,cache=none -net nic,macaddr=54:52:00:15:c4:50,vlan=0 -net tap,fd=16,script=,vlan=0,ifname=vnet0 -serial pty -parallel none -usb Supported machines are: pc Standard PC (alias of pc-0.12) pc-0.12 Standard PC (default) pc-0.11 Standard PC, qemu 0.11 pc-0.10 Standard PC, qemu 0.10 isapc ISA-only PC xenpv Xen Para-virtualized PC And my packages installed: # rpm -qa | grep qemu qemu-0.12.4-1.el5.rf # rpm -qa | grep kvm etherboot-zroms-kvm-5.4.4-13.el5.centos kmod-kvm-83-164.el5_5.12 kvm-83-164.el5_5.12 I haven't used CentOS as a KVM host yet, only Fedora, but your setup still puzzles me...why do you have a brand new qemu-package (as in not from the CentOS/RHEL repositories) installed? I would guess that this package would conflict with the kvm package and mess things up. Your error message mentions /usr/bin/qemu-system-x86_64 as the executable. If you run rpm -qf /usr/bin/qemu-system-x86_64 does it then tell you that this file belong to the qemu package? If so, I believe this is your problem...you try to use qemu, which has partial KVM support, instead of using qemu-kvm (which is the real KVM userspace executable that originates from the kvm package). I don't think the arguments supported by qemu-system-x86_64 and qemu-kvm are the same, which probably could be the cause of the client not booting and libvirt/virt-manager failing. Best Regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] 4 CPU with WinXP on Centos 5.5 KVM?
2010/5/28 Marcelino Mata mm...@multimatic.com: Has anyone had any success getting WinXP 32bit to use 4 CPU's under Centos 5.5 KVM? I have tried everything and the best I can get is 2 CPU's. I tried everything listed here http://www.linux-kvm.com/content/running-windows-smp-guests I am using the VIRTIO drivers. As it is discussed in the comments on the page you have linked above, XP only supports 2 CPUs but more cores. AFAIK KVM will always emulate CPUs not cores. Best Regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Libvirt NAT-based network 2x-4x faster than Libvirt routed network?
2010/5/28 compdoc comp...@hotrodpc.com: Maybe the part about netfilter? http://wiki.libvirt.org/page/Networking The part about disabling netfilter on bridges? It is already done, line 78-80: http://pastebin.com/jtTrHLqA ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Libvirt NAT-based network 2x-4x faster than Libvirt routed network?
2010/5/27 Veiko Kukk ve...@ekp.ee: On 05/27/2010 12:21 PM, Aleksei Miheev wrote: Is it typo? There can be no subnet with /32 bit mask, it's single host only. Actually, it is possible: ip addr add xxx.yyy.zzz.215/32 dev eth0 ip route add xxx.yyy.zzz.193 dev eth0 ip route add default via xxx.yyy.zzz.193 Of course you can do that, but it wouldn't a *subnet*. Net like network, system consisting of several units. I rest my case. Well, it is a subnet, it has just only got one host in it. I wrote it because the question is about routing, so it's quite relevant that the IP-addresses are not on the same subnet. No one with any clues on what to test / look into? :-/ Best Regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
[CentOS-virt] Libvirt NAT-based network 2x-4x faster than Libvirt routed network?
Hi Is it expected behaviour that a libvirt NAT-based network is faster than a libvirt routed network? I would guess that the routed network would be the fastest one in all cases, but I'm seeing the opposite in my setup. On a 100mbit internet connection, the routed network tops at 4mbyte/sec, while the nat-based network goes all the way to 10mbyte/sec. I've spend the last 6 hours on trying to figure out the cause of this, changing settings, reinstalling the system, but the problem persists and I can't find the cause of it. It is a clean and fairly simple setup: - Clean installation of CentOS 5.5 - Installation of kvm+libvirt+virt-manager+xorg - iptables service disabled - 1 public IP for the host (xxx.yyy.zzz.215) on a /32 subnet with xxx.yyy.zzz.193 as gateway - 3 public IP for the routed network (xxx.yyy.zzz.251-253) on a /26 subnet with the same gateway as the host - 1 virtual machine with either the NAT or the routed libvirt network assigned I have no networking connection errors or similar, it works perfectly with both the NAT and the routed network, but the routed network is just 2-4 times slower than the NAT one. Do you have any suggestions of what the problem might be? When I look at the iptables rules generated by libvirt, and the routing table, everything looks fine AFAICT. Traceroute from guest doesn't reveal anything either. Ping times from the two networks are similar, so the main issue seems to be throughput. Any help or pointers to what I should look at, is highly appreciated... :) I've copy pasted some of my relevant system configuration into pastebin: http://pastebin.com/jtTrHLqA Thank you, Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Moving vmware guests to a CentOS KVM server
2010/2/20 S.Tindall tindall.sat...@brandxmail.com: On Sat, 2010-02-20 at 02:41 +0100, Kenni Lund wrote: 2010/2/18 compdoc comp...@hotrodpc.com: I would also just use the e1000 emulation. Theres nothing better about the virtio devices... ...other than lower CPU utilization and higher throughout? Since these are CentOS/RHEL guests, I wouldn't even consider using e1000, I would just go for virtio_net. I don't have any links, but some time ago there were some benchmarks (on the KVM development list?), showing the e1000 maxing out at around 300-400mbit/s while the virtio got around 900mbit/s. Even with the much higher throughput, the virtio_net driver still had the same or lower CPU utilization. Do your own testing if in doubt. Best Regards Kenni Lund Are you using test-signed drivers or do you have a redistributable source for release-signed drivers (that chain to a microsoft root)? I don't think that anyone are talking about Windows in this thread? You don't need Microsoft signing of drivers for Linux guests ;) Never got the chance to test relative performance of e1000 vs the netkvm drivers on a M$ guest, but on a centos5 guest, virtio absolutely blows the doors off e1000 performance. Using ttcp in both directions, typical C5-host-to-C5-guests for e1000 was in the 30-60MB/s range and virtio was in the 300-400MB/s range. Exactly... :) Best Regards Kenni Lund ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Moving vmware guests to a CentOS KVM server
2010/2/18 compdoc comp...@hotrodpc.com: I would also just use the e1000 emulation. Theres nothing better about the virtio devices... ...other than lower CPU utilization and higher throughout? Since these are CentOS/RHEL guests, I wouldn't even consider using e1000, I would just go for virtio_net. I don't have any links, but some time ago there were some benchmarks (on the KVM development list?), showing the e1000 maxing out at around 300-400mbit/s while the virtio got around 900mbit/s. Even with the much higher throughput, the virtio_net driver still had the same or lower CPU utilization. Do your own testing if in doubt. Best Regards Kenni Lund ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] About doing backups with kvm guests
2009/12/16 m...@johestephan.de m...@johestephan.de: Hi all, As far as I know ist there no need to dd the hole disk. It should fit if you So just: - take the snap - mount it - pack it Yep, but you'll not be able to restore it into a bootable system again if you only backup the files. You could however, take a backup with dd of the partitiontable+bootloader and then afterwards backup the files of each partition. On a restore you would then copy back the partitiontable+bootloader, format the filesystems and copy the files back. But comparing this hacky solution to just using qcow2 on top of a Linux filsystem, the qcow2 solution seems much nicer :) Especially now when the qcow2 performance has been highly optimized: http://fedoraproject.org/wiki/Features/KVM_qcow2_Performance https://rhn.redhat.com/errata/RHSA-2009-1659.html Best Regards Kenni Lund ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] About doing backups with kvm guests
2009/12/12 Christopher G. Stach II c...@ldsys.net: - Kenni Lund ke...@kelu.dk wrote: I'm also very interested in how to make backups of Windows guests on LVM. But will the shadow copy feature in amanda not only backup the files within the Windows machine? I don't think I fully understand the method - How do you then do a full restore, eg. with no working Windows machine? Would you then have to do a clean install of Windows in order to get the partition and bootloader setup correctly, after which you can do the restore by overwriting all files? You can just shut down the VM, make a snapshot, start the VM, dd the snapshot, and finally drop the snapshot. Or, if that's too much downtime, you can xm save, snapshot, copy save dumpfile, xm restore, dd snapshot, backup dumpfile, and clean up. If that's too much downtime, you can xm pause, snapshot, xm unpause, etc., but you will have issues with your restore because it will look like the VM crashed and you may or may not lose data. Yeah, that's the problem. AFAIK if I want to take advantage of using LVM directly for Windows guests, I'll have to do a full dump with dd of the image/snapshot, including any unused bits...eventually combined with some compressing, but still. If I use a Linux filesystem on top of LVM and store the Windows guest in an image on this filesystem, the overall I/O performance will be lower, but I'll only have to backup data which are actually in use, due to sparse mode and/or the qcow2 image format (I'm using KVM). This is quite relevant if some machines have 200GB allocated HDD space, but only actively uses 30GB. Personally, I only back up data and never have useful data on a Windows installation volume (or even a native Windows volume, if I can help it). I can reimage a Windows machine with a single command and it only takes a few minutes. (Hint: use Sysprep.) Besides, reinstalling Windows machines is better than restoring them since they progressively bit rot. I agree, I already have backups of the important data, but some of these machines runs some old legacy software, which I for sure don't want to setup again unless it's extremely critical. Also, what I want is a minimal monthly full backup of each virtual machine, from which any of my (less technical) colleagues can restore to another physical server by following some simple guidelines. I think I'll stick with the extra layers (filesystem+image) for now to keep the setup simple and to keep the backups small. But thanks for your input. Best Regards Kenni Lund ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM Support for Windows Server 2003 32 bit ready for production?
2009/12/2 Kenni Lund ke...@kelu.dk: 2009/12/2 Neil Aggarwal n...@jammconsulting.com: I am wondering if KVM is ready for production for running a Windows Server 2003 32 bit guest. SNIP Well, the drivers works just fine for 64 bit guests, but they're tricky to install in their current form, since they _NEED_ to be signed correctly...if you sign them yourself, you'll need to enable test mode in Windows, which indeed is just as ugly as the add a secondary harddisk to install the virtio drivers fix. This is exactly why we need the virt-win package, which apparently both contain an iso with *.msi files for installing the drivers within Windows, as well as a floppy image for installation of drivers during the installation of Windows. The ugly part is the installation of unsigned VirtIO block device drivers...if you can live with e1000 NIC emulation (close to same performance, but a bit higher CPU utillization) and IDE emulation, then you shouldn't have any stability issues and no ugly hacks. Performance should still be fairly good. Just replying myself now :) If you want to test out the production readiness/stability of KVM with VirtIO without going through all the selfsigning stuff and manually copying the files back and forth from your virtual machines, feel free to use the following iso, which I created for my own use. It contains the latest binary drivers from http://www.linux-kvm.org/page/WindowsGuestDrivers/Download_Drivers, which afterwards have been self-signed with a test certificate, put into directories matching the names of the compatible Windows versions and compiled into an iso, which makes it easy to install, since you can just mount it directly into your virtual KVM machine. In order to test it on a Windows 2003 Server 32bit you don't need to enable any testsigning mode, you should just do the following: - Install Windows 2003 without any VirtIO devices - Shut it down -- Add a secondary HDD which uses the VirtIO interface -- Change the NIC to use the VirtIO interface -- Mount the iso as a cdrom in the virtual machine - Boot the system and point it towards the block and NIC drivers on the CD - Shut down the virtual machine - Remove the secondary HDD and change the primary to use VirtIO instead of IDE - Done I've uploaded the iso here, in case you want to try it out: http://www.student.dtu.dk/~kllu/VirtIO_24-09-2009.iso Best Regards Kenni Lund ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] CentOS-5.4, KVM, QEMU, Virt-Manager and kvm-qemu-img
2009/11/10 James B. Byrne byrn...@harte-lyne.ca: So, it would appear as if kvm-qemu-img is intended as a lightweight replacement for the full qemu package where all the functionality of the latter is not required. However, as I wish to use virt-manager clearly the full qemu package is required. No, it's not a replacement, it's a utility for handling image files, eg. create and convert harddisk images for QEMU/KVM. If you just install kvm libvirt virt-manager and all their dependencies, then you should be fine. Best Regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] CentOS-5.4, KVM, QEMU, Virt-Manager and kvm-qemu-img
2009/11/9 James B. Byrne byrn...@harte-lyne.ca: Further, do I need tun/tap to host VMs that themselves support virtual ips? The module for tun I found as part of the base install. But I cannot locate the module for ethertap and yum does not tell me where it is found. Yep, you do want tun/tap. But if you create a regular bridge and tells virt-manager or libvirt to use this for your virtual machines, virt-manager/libvirt will take care of the tun/tap setup. From your virtual machines point of view, tun/tap will get you the same connectivity as if you plugged a ethernet cable from your network into it, without any restrictions. Best Regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] CentOS-5.4, KVM, QEMU, Virt-Manager and kvm-qemu-img
2009/11/10 James B. Byrne byrn...@harte-lyne.ca: On Tue, November 10, 2009 09:16, Kenni Lund wrote: You need to configure your virtual machine to use a shared device, eg. your bridge. If your client gets a 192.168.122.x address, you've setup your virtual machine to use usermode networking. I have obtained the RedHat Virtualization Guide dated September 2009 and will go through that today and tonight. I know that eventually I will get this to work, but at the moment things appear very frustrating. Ok, once you get a grasp of it, I'm sure you'll find it pretty simple :) Install kvm + virt-manager + libvirt, setup a bridge, use virt-manager to create a new virtual machine which uses the bridge. Now you're done, nothing more needed. Best Regards Kenni ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] CentOS-5.4, KVM, QEMU, Virt-Manager and kvm-qemu-img
Ok, once you get a grasp of it, I'm sure you'll find it pretty simple :) Install kvm + virt-manager + libvirt, setup a bridge, use virt-manager to create a new virtual machine which uses the bridge. Now you're done, nothing more needed. The problem being is that I have already done all that and it simply does not work as expected. So I infer that there a few important details that everyone is leaving out of their descriptions, possibly because they assume them as preconditions. Hmm, try to have a look at this: http://www.linux-kvm.com/content/using-bridged-networking-virt-manager Like shown in the screenshot in section 4, you should select Shared physical device and then select your bridge in the drop-down menu. This should NOT give you usermode network (a 192.168.122.x address), this should instead connect the virtual machine to your network, meaning you can request a DHCP address if you have a DHCP server or assign a static IP inside the virtual machine. Best Regards Kenni Lund ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
