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.spies@xxxxxxxxx>:
RAM: 24 x 32GB DDR3-1866 2Rx4 LP ECC REG RoHS - 768GbCPU: 2 x Ivy Bridge 8C E5-2667V2 3.3G 25M 8GT/s QPI - 16 coresI 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.We are looking possibly the following hardware:
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.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)
