[CentOS-virt] poor performance with dom0 on centos7
keith.roberts at ecric.nhs.uk
Thu Sep 17 08:57:47 UTC 2015
On 2 Sep 2015, at 09:22, Pasi Kärkkäinen <pasik at iki.fi> wrote:
> On Tue, Sep 01, 2015 at 06:47:18AM +0200, Christoph wrote:
>> Hi All
>> it is possible to tune dom0/domU for better IO/network performance?
>> Since I have changed to Cenots7 dom0, I have a really poor IO
>> performance inside a PV VM.
>> I have already done what is described on
>> It is better now but still significantly worse than with centos6 dom0
>> my settings:
>> xen parameter: dom0_mem=1024M cpufreq=xen dom0_max_vcpus=2
>> xl sched-credit
>> Cpupool Pool-0: tslice=30ms ratelimit=1000us
>> Name ID Weight Cap
>> Domain-0 0 1024 0
>> samael 1 256 0
>> satan 2 512 0
>> amon 3 256 0
>> leviathan 4 512 0
>> echo 1048576 > /proc/sys/net/ipv4/tcp_limit_output_bytes on dom0
>> the both domU's satan and leviathan are very IO performance oriented
>> (NFS server and downloading vm)
>> Is there something more what I can do or try?
>> could it be a selinux issue? I have it in permissive mode there, not
>> disabled. But permissive means only to collect the info not enforcing
>> the rules...
>> (I use the xen45 pkgs)
> You forgot to mention the most important thing.. what kind of performance numbers are you seeing? What are you expecting?
Here’s a useful disk i/o stress test program that I got good results with on openSUSE 13.1, by running it on several VM’s overnight:
Using Bonnie++ for filesystem performance benchmarking
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