Re: Optimal settings for RAID controller - optimized for writes

On Sun, Feb 16, 2014 at 11:49 AM, Niels Kristian Schjødt
<nielskristian(at)autouncle(dot)com> wrote:
>
> Hi,
>
> I'm kind of a noob when it comes to setting up RAID controllers and tweaking them so I need some advice here.
>
> I'm just about to setup my newly rented DELL R720 12. gen server. It's running a single Intel Xeon E5-2620 v.2 processor and 64GB ECC ram. I have installed 8 300GB SSDs in it. It has an PERC H710 raid controller (Based on the LSI SAS 2208 dual core ROC).
>
> Now my database should be optimized for writing. UPDATEs are by far my biggest bottleneck.
>
> Firstly: Should I just put all 8 drives in one single RAID 10 array, or would it be better to have the 6 of them in one RAID 10 array, and then the remaining two in a separate RAID 1 array e.g. for having WAL log dir on it's own drives?
>
> Secondly: Now what settings should I pay attention to when setting this up, if I wan't it to have optimal write performance (cache behavior, write back etc.)?
>
> THANKS!
>
> BTW i attached a screenshot of some of the settings I can alter:

AFAIK, There isn't too much to do here (outside of mapping drives to
the array). The major question is about dedicating two drives for
WAL. I would consider dedicating that much SSD storage for WAL to be
gross overkill -- disk drives are better suited for that task. Which
model SSD are you using?

merlin