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

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

For resuming :

on RAID 0

        dom0: 80MB      domU:   56MB                    Loose: 30M

on RAID1

        dom0: 80MB      domU:  55 MB            Loose: 32%

on RAID5:

        dom0: 30MB      domU:   9MB                     Loose: 70%



So loose seem to be "exponantial" ?

 

>-----Message d'origine-----
>De : xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
>[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] De la part de 
>DOGUET Emmanuel
>Envoyé : mardi 24 février 2009 14:22
>À : Fajar A. Nugraha
>Cc : xen-users; Joris Dobbelsteen
>Objet : RE: [Xen-users] Re: Xen Disk I/O performance vs 
>nativeperformance:Xen I/O is definitely super super super slow
>
>
>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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