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.sp...@gmail.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) >
