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OpenVZ inside KVM
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OpenVZ inside KVM

jmginerjmginer Member, Patron Provider
edited February 2013 in General

Hi all, I want review my infra after 5 months in BETA and now 1 month in production.

We have deployed all our OVZ infra, installing the OVZ kernel on a KVM VPS.

We use Proxmox as a CloudDataCenter software.

A picture: http://t.co/pZDW6Qlp

Before starting the project, on Q3-2012, I try to find some review, everybody says that I will receive very poor performance... but wait! I'm using SSD disks, so I say that I will try.

Now, 6 months later and around 250 containers running on 6 KVM nodes ( 3 dedicated servers with 2 KVM VPS each one), the performance is Ok and not any problem related stability, (CentOS 6 has full support for VirtIO drivers).

Virtualization inside virtualization = More scalability and more backup options.
Hardware problem? -> I will migrate the KVM VPS, and I'm migrating several containers, yeah!

Maybe you are interested to hear this.

Best regards!

Comments

  • shovenoseshovenose Member, Host Rep

    I asked about this at some point and everybody said I should end up with poor performance and stability. Even though I felt that nobody had actually tried it.
    Thanks for the informative post.

  • jarjar Patron Provider, Top Host, Veteran
    edited February 2013

    Glad it's working for you. Having spent some time testing the same theory it was ultimately my conclusion (and contrary to previous statements) that it was one more potential point of failure and both the benefits and dangers were based on "what if."

    However, it's absolutely viable. Look forward to hearing more about your experience with it but I can't think of any questions to ask.

  • EvixoEvixo Member
    edited February 2013

    @jmginer Thanks for the information :-) Could you tell me what disk speeds you get on your host, KVM VPS and your OpenVZ VPS? (Just wondering what performance loss you have due to the virtualization layers).

  • jmginerjmginer Member, Patron Provider
    edited February 2013

    I use Intel 520 SSD Series

    This is the poor performance:

    [root@ovz1 ~]#
    [root@ovz1 ~]# vzctl enter 1552
    entered into CT 1552
    root@test-ovz1:/#
    root@test-ovz1:/# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
    16384+0 records in
    16384+0 records out
    1073741824 bytes (1.1 GB) copied, 5.91186 s, 182 MB/s
    root@test-ovz1:/#
    root@test-ovz1:/# rm -rf test
    root@test-ovz1:/#
    root@test-ovz1:/# exit
    logout
    exited from CT 1552
    [root@ovz1 ~]#

  • InfinityInfinity Member, Host Rep

    Mmm, it's definately been tried and am pretty sure it is used by some providers. It works but the performance isn't as good. IO doesn't mean everything, and the node once it gets filled up and once you use multiple ovz installations on one physical servers the performance will go down dramatically.

  • jmginerjmginer Member, Patron Provider

    Yes, we lost performance, around 50%, but still good as you can see. 180 MB/s is good acceptable.

    If I run directly on the Proxmox node Intel 520 series return +300 MB/s

    root@pveabs3:~# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
    16384+0 records in
    16384+0 records out
    1073741824 bytes (1.1 GB) copied, 3.2975 s, 326 MB/s
    root@pveabs3:~#
    root@pveabs3:~# qm list
    VMID NAME STATUS MEM(MB) BOOTDISK(GB) PID
    151 ovz1 running 14336 420.00 2316
    154 ovz4 running 14336 420.00 2390
    root@pveabs3:~#

    Regards!

  • jarjar Patron Provider, Top Host, Veteran

    What would interest me is seeing ioping results inside an OVZ container and then from the host node. That would be where it would really make or break.

  • jmginerjmginer Member, Patron Provider
    edited February 2013

    @jarland Check the IOping stats on the node.

    During backups -> less 100ms in waiting on /vz partition
    Not backup running -> less 30 ms in waiting

    http://bestpic.es/image/1360766866.png

    To verify inside the container, please, order one :)
    http://www.lowendtalk.com/discussion/7975/spain-leb-1vcpu1ghz-256-mb-mem-2-gb-ssd-100-gb-traffic-35year#Item_17

    Regards!

  • jarjar Patron Provider, Top Host, Veteran

    I mean like this

    ioping -c 10

    Around here it's become standard like the dd test to measure disk performance. Ideally it should be the same on both sides, just curious.

  • Munin's disk latency graphs != ioping results.

    Also, is this software raid?

  • jmginerjmginer Member, Patron Provider

    @jarland

    [root@ovz1 ~]#
    [root@ovz1 ~]# ioping -c 1 /vz
    4096 bytes from /vz (ext4 /dev/mapper/vz-vz): request=1 time=0.5 ms

    --- /vz (ext4 /dev/mapper/vz-vz) ioping statistics ---
    1 requests completed in 0.6 ms, 2028 iops, 7.9 mb/s
    min/avg/max/mdev = 0.5/0.5/0.5/0.0 ms
    [root@ovz1 ~]#
    [root@ovz1 ~]# vzctl enter 1552
    entered into CT 1552
    root@test-ovz1:/#
    root@test-ovz1:/# ioping -c 1 /
    4096 bytes from / (simfs /vz/private/1552): request=1 time=0.5 ms

    --- / (simfs /vz/private/1552) ioping statistics ---
    1 requests completed in 0.6 ms, 1876 iops, 7.3 mb/s
    min/avg/max/mdev = 0.5/0.5/0.5/0.0 ms
    root@test-ovz1:/# exit
    logout
    exited from CT 1552
    [root@ovz1 ~]#

  • jarjar Patron Provider, Top Host, Veteran

    Doesn't seem bad.

  • @jmginer said: Hardware problem? -> I will migrate the KVM VPS

    How do you migrate a KVM VPS if using local storage?

  • interesting

  • AnthonySmithAnthonySmith Member, Patron Provider

    Tried it and never had an issue with it, performance was absolutely fine for any real world application.

    Getting IPv6 working with proxmox and NAT IPv4 was tricky but possible.

  • MaouniqueMaounique Host Rep, Veteran

    I never said it will be horrible, in fact ovz is not real virtualization.
    I run frequently xen within KVMs both vanilla and XCP and while there are problems, they can be solved.
    With OVZ it should be even better performance.
    I think 50% performance loss is a bit much, could be tweaked further, imo.

  • raindog308raindog308 Administrator, Veteran

    Why stop there...go KVM -> Xen -> OvZ for the trifecta.

    Thanked by 1neps
  • AnthonySmithAnthonySmith Member, Patron Provider

    Well KVM well configured can be as little as 3% loss on native HW so why would OpenVZ inside KVM be anywhere close to 50%

  • MaouniqueMaounique Host Rep, Veteran

    @Jack said: I run Proxmox on a KVM with iperweb.

    Well, I and erawan run linux in windows with vmware and virtualbox on the windows server 2008RC2 LEB offer with only 512 ram. I had no lag except at install.
    That is linux HN/KVM windows/vmware linux

  • RobertClarkeRobertClarke Member, Host Rep

    I've personally never had great experiences with Intel SSDs.

  • It's funny I can install Proxmox in a Vmware VM but I can't install Vmware in a proxmox KVM..

    Althought the KVM option in proxmox did not work in a Vmware VM, OVZ worked great.

  • @Maounique said: Well, I and erawan run linux in windows with vmware and virtualbox on the windows server 2008RC2 LEB offer with only 512 ram. I had no lag except at install.

    Hehe... At first, after reading the thread tittle, I just remembered about running an Ubuntu Desktop inside a Windows 2008 KVM :D

  • doyou have debian os?

  • may set up is debian how ccan i set up my open vZ to debian thanks.. ineed your help.

  • Strictly speaking, OpenVZ isn't virtualization, it's container. So there's nothing that would prevent you from using OpenVZ from inside a true VM.

    Since namespaces development in Linux has advanced significantly since 2001, perhaps using LXC would be still faster.

  • yomeroyomero Member
    edited April 2018

    Necromancers

    But ok

    @david0923

    You should learn about proxmox (version 3), is a Debian based platform to install OpenVZ.

    Currently they are at the version 5, which doesn't support it, but works with LXC containers.

    Thanked by 1Shazan
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