Re: Specifications for a new server

I can suggest to have a disks' layout using at least two RAIDs:

1) RAID10 SSD (or 15kRPM HDD) SAS for O.S. and "pg_xlog" folder where PG
writes WAL files before checkpoint calls.
2) RAID10 using how many span is possible for the default DB folder.

Regards,

2014-05-06 11:13 GMT+02:00 Johann Spies <johann(dot)spies(at)gmail(dot)com>:

> I am busy reading Gregory Smith' s PostgreSQL 9.0 High Performance and
> when the book was written he seemed to me a bit sceptical about SSD's. I
> suspect the reliability of the SSD's has improved significantly since then.
>
> Our present server (128Gb RAM and 2.5 Tb disk space and 12 CPU cores -
> RAID 10) will become a development server and we are going to buy a new
> server.
>
> At the moment the 'base' directory uses 1.5Tb of disk space and there is
> still more data to come.
>
> The database contains blbliometric data that receive updates on a weekly
> basis but not much changes other than that except for cleaning of data by a
> few persons.
>
> Some of the queries can take many hours to finish.
>
> On our present system there are sometimes more than 300GB in temporary
> files which I suspect will not be the case on the new system with a much
> larger RAM.
>
> Analysis or the SAR-logs showed that there were too much iowait in the
> CPU's on the old system which has a lower spec CPU than the ones considered
> for the new system.
>
> We are looking possibly the following hardware:
>
> CPU: 2 x Ivy Bridge 8C E5-2667V2 3.3G 25M 8GT/s QPI - 16 cores
> RAM: 24 x 32GB DDR3-1866 2Rx4 LP ECC REG RoHS - 768Gb
>
> with enough disk space - about 4.8 Tb on RAID 10.
> My question is about the possible advantage and usage of SSD disks in the
> new server. At the moment I am considering using 2 x 200GB SSD' s for a
> separate partion for temporary files and 2 x 100GB for the operating system.
>
> So my questions:
>
> 1. Will the SSD's in this case be worth the cost?
> 2. What will the best way to utilize them in the system?
>
> Regards
> Johann
> --
> Because experiencing your loyal love is better than life itself,
> my lips will praise you. (Psalm 63:3)
>