Results 1 to 13 of 13

Thread: Xen & OpenVZ

  1. #1
    Join Date
    Nov 2005
    Location
    Spartanburg, SC
    Posts
    396

    Xen & OpenVZ

    hello all,

    i know xen is hardware based virtualization but is OpenVZ as well is the question
    Fully Managed | cPanel Shared Hosting | Windows Shared (coming soon) | R1Soft Daily Backups | FFmpeg packages
    Base 10 Hosting LLC
    follow us on twitter - @Base10Hosting

  2. #2
    Join Date
    Dec 2005
    Posts
    3,077
    OpenVZ is known as OS level virtualization. All processes running inside an OpenVZ VPS are visible on the host node.

    The main difference between the two is the isolation, and also the fact Xen provides Swap like a Dedicated Server, whereas OpenVZ provides Burstable Ram.

    I would say that my personal preference is Xen, since we specialise on Xen Virtual Servers. The main reason for this is that Xen is more suited towards heavier/more resource intensive applications. With OpenVZ the load of a VPS also affects the load of the node and therefore other VPS on the node, as well as the fact that any processes using burst ram can be killed off at any time by the kernel. On Xen when you run out of Ram your VPS will start Swapping like a Dedicated server, so things become slower instead of crashing. The main "selling point" as it were for me, is that one Xen VPS can be running cpu intensive applications without having any impact on other VPS on a node.

    To summarise the two

    OpenVZ - OS Level virtualisation = Less overheads so slightly better performance in theory. Strictly speaking it depends on the number of VPS on the node and the hardware etc.

    Xen - HW Level virtualisation = A little more overhead, but much more isolated in comparison to OpenVZ, and more customizable e.g. loadable kernel modules.

    Hope this helps!
    Last edited by PCS-Chris; 03-06-2008 at 05:41 PM.

  3. #3
    Join Date
    Nov 2005
    Location
    Spartanburg, SC
    Posts
    396
    cool thanks chris can you send me a message i have some mor edirect questions about Xen...
    Fully Managed | cPanel Shared Hosting | Windows Shared (coming soon) | R1Soft Daily Backups | FFmpeg packages
    Base 10 Hosting LLC
    follow us on twitter - @Base10Hosting

  4. #4
    Join Date
    Sep 2005
    Location
    Canada
    Posts
    645
    I'm biased the other way, OpenVZ rather than Xen.

    Both have their place, but I'd summarize as follows:

    If you need to compile your own kernel, or you need your own swap space, use Xen. Xen simulates your own hardware and provides your own bios, simulated cpu and chipset etc. There is a heavy price for this in terms of performance but you get total isolation.

    If you don't need those features, OpenVZ is superior in performance and cost.

    Instead of simulating a cpu, chipset and bios, openvz just simulates your own kernel. You run your own OS under this simulated kernel.

    A VPS running on OpenVZ has dedicated cpu time, disk access speed and memory. Other uses can max out their usage and you shouldn't notice a decrease in speed at all. Memory that is unused by other uses can be used by you (burst memory).

    Xen is also slower because of the swapping done by other users. Disk IO is the biggest limiting factor in VPS performance. More swapping means lower performance for everyone. OpenVZ servers have a lot less disk IO going on so feel 'snappy' when you issue commands.

    A good provider will undersell the boxes slightly to ensure some burst is always available, and performance is always snappy.

    Anyway, I suggest you try both and see what you actually need. You can get a small vps for 10$ from some places, which is good enough for a test. You can even get your money back if you don't like it.
    VPSVille.com
    Toronto, London, Dallas, Los Angeles
    Quality VPS hosting on Premium bandwidth

  5. #5
    Join Date
    Apr 2007
    Location
    New York
    Posts
    422
    Again, I personally use openVZ.

    I believe it provides better performance.

    (Boy isnt this a big post like the ones above )

  6. #6
    Join Date
    Jun 2005
    Posts
    325

    Talking

    Quote Originally Posted by magnuson56 View Post
    (Boy isnt this a big post like the ones above )
    LOL

    Sorry can't help but react to this.

  7. #7
    Can open VZ be used with iSCSI storage?

  8. #8
    Quote Originally Posted by hostbyr View Post
    Can open VZ be used with iSCSI storage?
    That depends on what you want to do with it, but iSCSI storage appears as normal block devices under linux, so you should have no problems.

    Regards,
    Jorge Luis

  9. #9
    Join Date
    May 2007
    Posts
    41
    Sorry to bump into this, but which one would you recommend for if I am hosting only personal websites on a dedicated server which will have only one VPS? Going by the above arguments, OpenVZ seems to be the option for me for performance issues

    But, on the other hand, my sites have peaks during some times of the day and therefore, I do not want the processses to be killed. I would want some swap usage? This I think makes XEN better?

    Which one do you think is better in my situation?

  10. #10
    Join Date
    Feb 2004
    Posts
    371
    As some of the past posters said. Some people are biased and with different thoughts on the two of them. Personally, I see Xen as "true" virtualization, as it does it on a hardware level, whereas Xen deals alot more with the Host OS, even kernel, etc.

    I like isolation, true isolation where one vps can't hurt it's neighbor.

    If you ask me, I'd say Xen, hands down. Its up to you, to say which is better suited for your needs.

  11. #11
    Join Date
    Nov 2005
    Location
    Michigan, USA
    Posts
    3,872
    Quote Originally Posted by hostbyr View Post
    Can open VZ be used with iSCSI storage?
    It depends, iSCSI with ext3 doesn't allow for shared storage. Therefore, you can't share the iSCSI partition between servers, and OpenVZ requires ext3 in order for the quotas to work correctly.

    So yes it will work, but you can either go without shared storage or working quotas.


  12. #12
    Join Date
    Nov 2005
    Location
    Michigan, USA
    Posts
    3,872
    Quote Originally Posted by carlostabs View Post

    I like isolation, true isolation where one vps can't hurt it's neighbor.
    .
    Either way, a VPS can still hurt it's neighbors. It is still all on one system, with OpenVZ you can set the io priority, cpu limit, cpu priority and set many other limits if necessary to try and avoid one vps from bringing down the rest.

    I don't really see how Xen would be any different, sure it's hardware virtualization, but one server with a very high load or high disk usage could still greatly affect the others.

    There isn't a technology yet that can guarantee one VPS won't affect the neighbors.


  13. #13
    Join Date
    Feb 2004
    Posts
    371
    I don't really see how Xen would be any different, sure it's hardware virtualization, but one server with a very high load or high disk usage could still greatly affect the others.
    Tha only reason a server could be slowed down by a VPS is with excessive swapping.

    Xen won't share resources the same way OpenVZ does. Do some more research on Xen, and even try it out yourself.

    Also, OpenVZ is open to overselling, while Xen is not. (it just won't add more VPS's after you allocated it all).

    OpenVZ shares resources 'better' than Xen, giving them more flexibility on VPS's on a machine, etc, while Xen will not share any allocated resources. This is the MAIN reason providers go for OpenVz, it is the biggest benefit it offers.

    You can be biased, and I may be too , but just research on the technicals on Xen and technicals on Virtuozzo or Openvz.

    Best of luck mate.

    here's a great response from another Xen vs OpenVz thread

    " OpenVZ and Xen use different virtualization approaches: OpenVZ uses OS level virtualization, while Xen uses paravirtualization. This is a pretty significant difference and proponents of each will argue it to their advantage. OpenVZ folks will say their approach allows for better resource usage and density. We feel paravirtualization provides good resource usage and superb isolation. Translation: your neighbor can’t bring the whole box down.

    Xen also requires fixed memory and disk definitions, OpenVZ allows for burstable memory usage. That is the biggest difference you will see, burstable memory rates on Virtuozzo offerings, whereas Xen has hard, fixed caps. Burstable memory is great if you have control over all of the virtual servers (everyone is friendly), but when you have a diverse environment like ours, we prefer hard memory caps (you get what you pay for). "
    Last edited by ctaborda; 05-10-2008 at 01:18 PM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •