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On 06/29/2015 07:19 AM, Narayanan, Krishnaprasad wrote:
> Hello all,
>
> I ran tests under the following settings to measure the IO performance
> of MySQL database. I used Sysbench as the client workload generator. I
> found that the performance of MySQL (both resource utilization and
> application) has degraded by more than 50% after switching from setting
> a) to setting b).
>
> Setting a): Controller & Compute node OS - Ubuntu 12.04, cloud software:
> OpenStack Havana, networking: nova-network, Hypervisor: KVM, Libvirt
> version: 1.1.1, QEMU version: 1.5.0, Host disk write cache: enabled,
> Guest disk cache: none and host OS scheduler: CFQ.
>
> Setting b): Controller & Compute node OS - Ubuntu 14.04, cloud software:
> OpenStack Icehouse, networking: Neutron, Hypervisor: KVM, Libvirt
> version: 1.2.2, QEMU version: 2.0.0, Host disk write cache: enabled,
> Guest disk cache: none and host OS scheduler: CFQ.
>
> May I know has anybody performed such tests and if yes, can you please
> share details on the IO performance of VMs and the application?
>
> I don’t know whether is the right question to ask in this forum. Can
> somebody share information at a high level about the improvements made
> in Libvirt (from version 1.1.1 to 1.2.2) for handling IO requests?

Since you changed so many variables between setting a) and b), there's 
no possible way to say which one of those changes resulted in the 
degraded performance of MySQL.

You also have not given the different versions of MySQL you were 
running, nor provided the diffs of the my.cnf settings you used...

I'd recommend trying to reduce the delta of your environment changes and 
then re-running sysbench.

Best,
-jay