Hi,
i recently run pgbench against different servers and got some results I dont quite understand.


A) EV1: Dual Xenon, 2GHz, 1GB Memory, SCSI 10Krpm, RHE3
B) Dual Pentium3 1.4ghz (Blade), SCSI Disk 10Krmp, 1GB Memory, Redhat 8
C) P4 3.2GHz, IDE 7.2Krpm, 1GBMem, Fedora Core2

All did run only postgres 7.4.6

pgconf settings:
max_connections = 100
shared_buffers = 8192
sort_mem = 8192
vacuum_mem = 32768
max_fsm_pages = 200000
max_fsm_relations = 10000
wal_sync_method = fsync wal_buffers = 64 checkpoint_segments = 10 effective_cache_size = 65536
random_page_cost = 1.4


/etc/sysctl.conf
shmall and shmmax set to 768mb


Runnig PGbench reported A) 220 tps B) 240 tps C) 510 tps

Running hdparm reported
A) 920mb/s   (SCSI 10k)
B) 270mb/s   (SCSI 10k)
C) 1750mb/s  (IDE  7.2k)

What I dont quite understand is why a P3.2 is twice as fast as a Dual Xenon with SCSI disks, A dual Xenon 2GHz is not faster than a dual P3 1.4Ghz, and the hdparm results also dont make much sense.

Has anybody an explanation for that? Is there something I can do to get more performance out of the SCSI disks?

Thanks for any advise
Alex



















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