Re: Setting effective_io_concurrency in VM?

Whats the guest OS? I have been able to get Oracle to perform just as well
on Virtuals as it does on Physicals. I suspect the settings are pretty
similar.

On Mon, Nov 27, 2017 at 3:06 PM, Fernando Hevia <fhevia(at)gmail(dot)com> wrote:

>
>
> El 27 nov. 2017 15:24, "Don Seiler" <don(at)seiler(dot)us> escribió:
>
> Good afternoon.
>
> We run Postgres (currently 9.2, upgrading to 9.6 shortly) in VMWare ESX
> machines. We currently have effective_io_concurrency set to the default of
> 1. I'm told that the data volume is a RAID 6 with 14 data drives and 2
> parity drives. I know that RAID10 is recommended, just working with what
> I've inherited for now (storage is high-end HP 3Par and HP recommended RAID
> 6 for best performance).
>
> Anyway, I'm wondering if, in a virtualized environment with a VM
> datastore, it makes sense to set effective_io_concurrency closer to the
> number of data drives?
>
> I'd also be interested in hearing how others have configured their
> PostgreSQL instances for VMs (if there's anything special to think about).
>
>
>
> If the storage was exclusively for the Postgres box I'd try
> effective_io_concurrency somewhere between 8 and 12. Since it is probably
> not, it will depend on the load the other VMs exert on the storage.
> Assuming the storage isnt already stressed and you need the extra IOPS, you
> could test values between 4 and 8. You can of course be a lousy team player
> and have PG paralelize as much as it can, but this eventually will piss
> off the storage or vmware manager, which is never good as they can limit
> your IO throughput at the virtualization or storage layers.
>
> Cheers.
>
>
>
>

--
Andrew W. Kerber

'If at first you dont succeed, dont take up skydiving.'