Re: [libvirt-users] How to best I/O performance for Window2008 and MSSQL guest VM
Hi Roberto,
On 6 December 2016 at 19:01, Roberto Fichera <kernel(a)tekno-soft.it> wrote:
I've set to copy host configuration (16 cores) and memory is set
to 24GB, host has 64GB.
Guest is Windows 2012 64bits version
Is the guest configured with 16 cpus or 16 cores?
> Are you pinning to dedicated CPUs,
no
I would, to ensure cpu or cache performance is absolutely not a
problem, and it's simple to do (see vcpupin).
> are you exposing host topology and cpu
> features,
Yes
So you have something like:
<cpu mode='host-passthrough'>
<topology sockets='1' cores='8' threads='2'/>
In your domain xml?
> do you have dedicated I/O threads?
if you are talking about disk I/O, no. Should I do that?
Hard to say what the problem is without a lot more information - maybe
the system in question is performance limited by the DB design...
But if you are bottlenecking on I/O in the guest whilst the host seems
to have more I/O available then you probably want to consider tuning
this:
https://libvirt.org/formatdomain.html#elementsIOThreadsAllocation
> Are you backing the guest memory with hugepages?
Don't know, how can I check or set it?
You can either use transparent huge pages (assuming you are not doing
any PCI passthrough), or create a static hugepage allocation for
guests. Search for documentation specific to your OS.
--
Cheers,
~Blairo