RE: [Xen-users] Re: Xen Disk I/O performance vs native performance:Xen I/O is definitely super super super slow

["DOGUET Emmanuel" <Emmanuel.DOGUET@xxxxxxxx>]

I have made another test on another server (DL 380)

And same thing!

I'm always use this test :

dd if=/dev/zero of=TEST bs=4k count=1250000

(be careful with memory cache)


TEST WITH 2 RAID 5 (include system on RAID 5, 3x146G + 3x146G)
---------------------------------------------------------------

 dom0: 1GO, 1CPU, 2 RAID 5

        rootvg(c0d0p1):         4596207616 bytes (4.6 GB) copied, 158.284 
seconds, 29.0 MB/s
        datavg(c0d1p1):         5120000000 bytes (5.1 GB) copied, 155.414 
seconds, 32.9 MB/s

domU: 512M, 1CPU         on System LVM/RAID5 (rootvg)

        5120000000 bytes (5.1 GB) copied, 576.923 seconds, 8.9 MB/s

domU: 512M, 1CPU         on DATA LVM/RAID5 (datavg)

        5120000000 bytes (5.1 GB) copied, 582.611 seconds, 8.8 MB/s

domU: 512M, 1 CPU on same RAID without LVM

        5120000000 bytes (5.1 GB) copied, 808.957 seconds, 6.3 MB/s


TEST WITH RAID 0 (dom0 system on RAID 1)
---------------------------------------

dom0   1GO RAM 1CPU

        on system (RAID1):
        i3955544064 bytes (4.0 GB) copied, 57.4314 seconds, 68.9 MB/s

        on direct HD (RAID 0 of cssiss), no LVM
        5120000000 bytes (5.1 GB) copied, 62.5497 seconds, 81.9 MB/s

dom0   4GO RAM 4CPU



domU:  4GO, 4 CPU

        on direct HD (RAID 0), no LVM.
        5120000000 bytes (5.1 GB) copied, 51.2684 seconds, 99.9 MB/s


domU: 4GO, 4CPU  same HD but ONE LVM on it

        5120000000 bytes (5.1 GB) copied, 51.5937 seconds, 99.2 MB/s


TEST with only ONE RAID 5 (6 x 146G)
------------------------------------

dom0 : 1024MB - 1CPUI (RHEL 5.3)

        5120000000 bytes (5.1 GB) copied, 231.113 seconds, 22.2 MB/s


512MB - 1 CPU
        5120000000 bytes (5.1 GB) copied, 1039.42 seconds, 4.9 MB/s


512MB - 1 CPU - ONLY 1 VDB [LVM] (root, no swap)

        (too slow ..stopped :P)
        4035112960 bytes (4.0 GB) copied, 702.883 seconds, 5.7 MB/s

512MB - 1 CPU - On a file (root, no swap)

        1822666752 bytes (1.8 GB) copied, 2753.91 seconds, 662 kB/s

4GB - 2 CPU
        5120000000 bytes (5.1 GB) copied, 698.681 seconds, 7.3 MB/s




>-----Message d'origine-----
>De : Fajar A. Nugraha [mailto:fajar@xxxxxxxxx] 
>Envoyé : samedi 14 février 2009 06:23
>À : DOGUET Emmanuel
>Cc : xen-users
>Objet : Re: [Xen-users] Re: Xen Disk I/O performance vs native 
>performance:Xen I/O is definitely super super super slow
>
>2009/2/13 DOGUET Emmanuel <Emmanuel.DOGUET@xxxxxxxx>:
>>
>>
>> I have mount domU partition on dom0 for testing and it's OK.
>> But same partiton on domU side is slow.
>>
>> Strange.
>
>Strange indeed. At least that ruled-out hardware problems :)
>Could try with a "simple" domU?
>- 1 vcpu
>- 512 M memory
>- only one vbd
>
>this should isolate whether or not the problem is on your particular
>domU (e.g. some config parameter actually make domU slower).
>
>Your config file should have only few lines, like this
>
>memory = "512"
>vcpus=1
>disk = ['phy:/dev/rootvg/bdd-root,xvda1,w' ]
>vif = [ "mac=00:22:64:A1:56:BF,bridge=xenbr0" ]
>vfb =['type=vnc']
>bootloader="/usr/bin/pygrub"
>
>Regards,
>
>Fajar
>

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