I have a beast of a Dell server with the following specifications: - 4x Xeon E5-4657LV2 (48 cores total) - 196GB RAM - 2x SCSI 900GB in RAID1 (for the OS) - 8x Intel S3500 SSD 240GB in RAID10 - H710p RAID controller, 1GB cache
Centos 6.6, RAID10 SSDs uses XFS (mkfs.xfs -i size=512 /dev/sdb). Here are some relevant postgresql.conf settings: shared_buffers = 8GB work_mem = 64MB maintenance_work_mem = 1GB synchronous_commit = off checkpoint_segments = 256 checkpoint_timeout = 10min checkpoint_completion_target = 0.9 seq_page_cost = 1.0 effective_cache_size = 100GB I ran some "fast" pgbench tests with 4, 6 and 8 drives in RAID10 and here are the results: time /usr/pgsql-9.1/bin/pgbench -U postgres -i -s 12000 pgbench # 292GB DB 4 drives6 drives8 drives105 min98 min94 min /usr/pgsql-9.1/bin/pgbench -U postgres -c 96 -T 600 -N pgbench # Write test 4 drives6 drives8 drives656774278073 /usr/pgsql-9.1/bin/pgbench -U postgres -c 96 -T 600 pgbench # Read/Write test 4 drives6 drives8 drives365154747203 /usr/pgsql-9.1/bin/pgbench -U postgres -c 96 -T 600 -S pgbench # Read test 4 drives6 drives8 drives176282548228698 A few notes: - I ran these tests only once, so take these number with reserve. I didn't have the time to run them more times, because I had to test how the server works with our app and it takes a considerable amount of time to run them all. - I wanted to use a bigger scale factor, but there is a bug in pgbench with big scale factors. - Postgres 9.1 was chosen, since the app which will run on this server uses 9.1. - These tests are with the H710p controller set to write-back (WB) and with adaptive read ahead (ADRA). I ran a few tests with write-through (WT) and no read ahead (NORA), but the results were worse. - All tests were run using 96 clients as recommended on the pgbench wiki page, but I'm sure I would get better results if I used 48 clients (1 for each core), which I tried with the R/W test and got 7986 on 8 drives, which is almost 800TPS better than with 96 clients. Since our app is tied to the Postgres performance a lot, I'm currently trying to optimize it. Do you have any suggestions what Postgres/system settings I could try to tweak to increase performance? I have a feeling I could get more performance out of this system. Regards, Strahinja
