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Xen vs KVM

Xen vs KVM

KairusKairus Member
edited November 2011 in General

What do you guys feel is better? From a host and client viewpoint (which would you rather host or buy?).

http://www.phoronix.com/scan.php?page=article&item=ubuntu_1110_xenkvm&num=1 That benchmark is pretty interesting, it definitely shows KVM outperforms Xen,

Besides Xen being older, and more widely used (from what I've read), I can't see any reason to use it now.

If you were in the market for a VPS, and you saw a Xen and KVM at roughly equivalent prices/specs, which would you go for?

(I couldn't find any posts related to this using search since KVM/Xen are only three letter words)

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Comments

  • Virtualbox is crap and crashes all the time due to terrible kernel drivers.

    cederic has a fairly IO intensive instance and home and it panic's all the time.

    Francisco

    BuyVM - OpenVZ & KVM Based / TUN, PPTP, FUSE, SIT & GRE Enabled! / Stallion Control Panel
  • yomeroyomero Member
    edited November 2011
  • Remember, that benchmark was testing Xen HVM, not PV!

    Preetam @ Bitcable

  • KairusKairus Member
    edited November 2011

    @giang said: You should go to the OP link :P

    Yeah, but I linked that to show the performance difference between Xen HVM and KVM. I don't know why virtualbox is in that benchmark, kind of odd.

    @Bitcable Isn't Xen HVM most comparable to KVM?

    /Offtopic for this thread, how come nobody uses LXC?

  • @Kairus said: @Bitcable Isn't Xen HVM most comparable to KVM?

    Yes, but I wanted to make sure people knew the difference ;)

    Preetam @ Bitcable

  • yomeroyomero Member
    edited November 2011

    @giang said: You should go to the OP link :P

    Oh, got it :P

    @Kairus said: /Offtopic for this thread, how come nobody uses LXC?

    What I've read, is that LXC doesn't provide a decent level of isolation as OpenVZ

  • bretonbreton Member
    edited November 2011

    Xen doesn't allow overselling (yes, I know about balooning). KVM does.

    @Kairus said: If you were in the market for a VPS, and you saw a Xen and KVM at roughly equivalent prices/specs, which would you go for?

    It is like choosing between Xen and OpenVZ. If the provider has both of these types and has a hard and good limit on the number of VPSes on the node for KVM, I'll choose KVM. If I have any doubts - Xen.

  • @breton are you talking about Xen HVM or PV?

  • @Kairus said: Isn't Xen HVM most comparable to KVM?

    Xen HVM - KVM - Xen PV.

    something like that. they're in different class.

    @Kairus said: /Offtopic for this thread, how come nobody uses LXC?

    i have that one, in my dev server with debian 6.. i'm looking to put KVM and LXC in my own control panel, but still have a lot bug.

    and i have bad experience with Xen (HVM) when all my drive broken.

    Yes! I'm with Carstensz Pyramid Server Now stop asking me please :D
  • @Kairus said:

    @breton are you talking about Xen HVM or PV?

    Err, any difference refering to my post?

  • xen pv to replace openvz kvm to replace xen hvm

    :-)

  • kiloservekiloserve Member
    edited November 2011

    @Kairus said: If you were in the market for a VPS, and you saw a Xen and KVM at roughly equivalent prices/specs, which would you go for?

    KVM has surpassed Xen HVM in terms of performance. As you said, I can't really see a reason to use Xen-HVM anymore over KVM.

    XenPV is still faster than KVM.

    So if you're talking about Xen HVM, then I'd go with KVM.

    If you're comparing XenPV vs KVM, I'd go with XenPV if you're going to be running basic Linux. KVM can run most BSD's and Windows.

    But as always it's up to the provider to set the proper overselling limits...even faster virtualization can be slower due to server overloading.

  • Agree with what most people have said, I would use KVM over Xen HVM.

  • @kiloserve said: XenPV is still faster than KVM.

    I dunno about that.... If you use newer CPU's and pass some extra flags you can get a crap load of performance from it :) We got an internal box we do our dev/etc on and it runs like a champ:

    dd if=/dev/zero of=test bs=1M count=2k conv=fdatasync 2048+0 records in 2048+0 records out 2147483648 bytes (2.1 GB) copied, 3.82459 seconds, 561 MB/s

    8 x 500G drives in RAID10.

    Granted, without the tuning it'll only bench about half that.

    Francisco

    BuyVM - OpenVZ & KVM Based / TUN, PPTP, FUSE, SIT & GRE Enabled! / Stallion Control Panel
  • kiloservekiloserve Member
    edited November 2011

    @Francisco said: dd if=/dev/zero of=test bs=1M count=2k conv=fdatasync 2048+0 records in 2048+0 records out 2147483648 bytes (2.1 GB) copied, 3.82459 seconds, 561 MB/s

    8 x 500G drives in RAID10.

    Wow that's fast. :)

    In our side of pre-production testing, XenPV runs quite a bit faster than KVM. Even disk I/O was faster than KVM.

    And on our production boxes, CPU usage is about 5% on a loaded XenPV as opposed to about 15% CPU usage on a fully loaded KVM. Since the RAM amount is the same across the boxes the number of VPS is roughly the same. Not quite apples to apples but it takes roughly 10% more CPU power to deliver roughly the same number of VPS.

    And as the KVM nodes are loaded up, the disk I/O drops more rapidly than it does on XenPV.

    Like on KVM, we started at around 450 MB/s fresh and it dropped down to about 330MB/s once it's fully loaded up.

    On XenPV we start at 370MB/s and it pretty much stays at 340MB/s once fully loaded. Very little drop on XenPV.

  • MrAndroidMrAndroid Member
    edited November 2011

    KVM + Virsh + libvert is terrible.

    Always use to bug on me.

    Also, I found KVM has a issue of randomly memory leaking and CPU hanging, I ran one KVM VM on my home laptop, and while running a basic setup of Debian 6, started to topple up to 2.5GB of memory as well as 100% CPU.

    The Original Daniel.

  • @Daniel said: KVM + Virsh + libvert is terrible.

    Don't hate on libvirt! It's magical!

    Preetam @ Bitcable

  • We working with OpenVZ, its cool tool.

  • InfinityInfinity Retired Staff

    spam..

    This thread is about Xen and KVM. Anyways, ovz is generally surpased in performance by Xen and KVM.

    我是一个巨魔 (;

  • Balticservers your not off to the best of starts around here are you.

  • @Bitcable said: Don't hate on libvirt! It's magical!

    I don't know how you can say that, its like hell.

    The Original Daniel.

  • @VMPort said: Balticservers your not off to the best of starts around here are you.

    Yeah, it's strange, pretty irreal. Would make me wonder if they are really stupid or if it's a competitor that came here to destroy the company...

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