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>]

I have finished my tests on 3 servers. On each we loose some bandwidth with 
XEN. On our 10 platform ... We always loose some bandwidth, I think it's 
normal. Just the bench method who must differ?

I have made bench (write only) between hardware and software RAID under XEN 
(see attachment).

Linux Software RAID is always faster than HP Raid. I must try too the 
"512MB+Cache Write" option for the HP Raid.

So my problems seem to be here.


-------------------------
HP DL 380
Quad core
-------------------------
Test: dd if=/dev/zero of=TEST bs=4k count=1250000



          Hardware     Hardware    Software     Software
           RAID 5        RAID 5      RAID 5       RAID 5
          4 x 146G      8 x 146G   4 x 146G     8 x 146G
dom0 
(1024MB,
 1 cpu)     32MB        22MB        88MB (*)    144MB (*)

domU 
( 512MB,
 1 cpu)      8MB        5MB         34MB        31MB
 
domU
 (4096MB,
 2 cpu)     --          7MB         51MB        35MB



*: don't understand this difference.


This performance seems to be good for you?




         Best regards.




>-----Message d'origine-----
>De : DOGUET Emmanuel
>Envoyé : mardi 24 février 2009 17:50
>À : DOGUET Emmanuel; 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
>
>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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>>

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