Cores on PVE config - Performance

[TiagoRF]

Hello all,

I'm experiencing some slow performance on an exchange server.

We had installed PVE 1.4, and as soon as we saw the PVE 1.5 we immediatly wanted to change.

So we did it, we did not upgrade, as we dislike to upgrade, we snapshot'd all the vm's and formated the servers, clean 1.5 install and restored the vm's

All like a charm!

However, the performance was not what we expected, and Exchange server is pretty much like dying..

Here's the cfg:

name: SRVEX
ide2: cdrom,media=cdrom
bootdisk: ide0
ostype: w2k8
ide0: local:107/vm-107-disk-1.raw
memory: 5120
onboot: 0
sockets: 2
cores: 2
ide1: local:107/vm-107-disk-2.raw
ide3: local:107/vm-107-disk-3.raw
boot: c
freeze: 0
cpuunits: 1000
acpi: 1
kvm: 1
vlan3: e1000=66:1F:F5:28:7E:FE
vlan2: e1000=1A:7B:11:72:04:C3

Any suggestion to speed this up?

CPUUNITS: 1000 - does anyone know what is this for?

Cores: 2, sockets 2

I've been trying to set this to 4 cores, 2 sockets - in order to have 8 cores in this server, but no success, only 2x2 or 2x1 or even 1x1 works.

Im willing to take your ideas!

Cheers

Tiago

 

[TiagoRF]

PS: i'll be changing to virtio disks tonight, already tried it with a previously restore, works well, and better, but not enough!

 

[tom]

make sure you have the latest KVM (0.12.4) - I suggest you compare the performance from one vCPU against four vCPU. I assume I/O will be better with one vCPU.

 

[TiagoRF]

Hello tom,

Thanks for the sugestion, i'll try it on this weekend, after the snapshot is done.

 

[TiagoRF]

Hi tom,

I did a little experience in a minor server, it had 2x2 (4cores) and i've tried it with 1x1 and 2x1, the performance was pretty awful..

The performance regarding exchange, its just inside the machine, console/rdp.

Opening software inside the server is dead slow, the overall performance for mail delivery etc etc is quite fast!

It's just over vnc/rdp, sorry for missing that point!