Hi
Im now pretty sure the problem is the DomU with NFS Server.
If I write on a NFS share from other Host (bare metal or other vm) then
I see on my NFS server nearly the whole time 100% io at [jbd2/dm-5-8]
process...
If I write on a SMB share (same partition as nfs share) from other Host
then it is a little bit better but still ever and ever again 100% io
load
If I write a 1GB file on the same partition (with nfs/samba share) with
dd, I dont see the high io load...
Is there a known problem with nfs/smb shares and/or dm in xen domU's on
centos 7 as dom0? With centos 6 as dom0 I didnt had the problem...
(the partition with the shares is a raid5 software partition, soft raid
is build in dom0 and as a xvd device passed through to the domU with the
shares)
could selinux be the problem? I have it in permissive mode on all hosts
here (dom0 and domU) not disabled...
Any hints for me?
Am 2015-09-01 06:47, schrieb Christoph:
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
http://wiki.xenproject.org/wiki/Tuning_Xen_for_Performance
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
dom0_vcpus_pin
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)
--
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Greetz
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