Alexandre Barros wrote:
Hello,
i have a pg-8.0.3 running on Linux kernel 2.6.8, CPU Sempron
2600+, 1Gb RAM on IDE HD ( which could be called a "heavy desktop" ),
measuring this performance with pgbench ( found on /contrib ) it gave
me an average ( after several runs ) of 170 transactions per second;
That is going to be because IDE drives LIE about write times because of
the large cache.
for the sake of experimentation ( actually, i'm scared this IDE drive
could fail at any time, hence i'm looking for an alternative, more
"robust", machine ), i've installed on an aging Compaq Proliant server
( freshly compiled SMP kernel 2.6.12.5 with preemption ), dual
Pentium III Xeon 500Mhz, 512Mb RAM, (older) SCSI-2 80pin drives, and
re-tested, when the database was on a single SCSI drive, pgbench gave
me an average of 90 transactions per second, but, and that scared me
most, when the database was on a RAID-5 array ( four 9Gb disks, using
linux software RAID mdadm and LVM2, with the default filesystem
cluster size of 32Kb ), the performance dropped to about 55
transactions per second.
That seems more reasonable and probably truthful. I would be curious
what type of performance you would get with the exact same
setup EXCEPT remove LVM2. Just have the software RAID. In fact, since
you have 4 drives you could do RAID 10.
i wouldn't be so stunned if the newer machine was ( say ) twice faster
than the older server, but over three times faster is disturbing.
the postgresql.conf of both machines is here:
max_connections = 50
shared_buffers = 1000 # min 16, at least max_connections*2,
8KB each
You should look at the annotated conf:
http://www.powerpostgresql.com/Downloads/annotated_conf_80.html
Sincerely,
Joshua D. Drake
debug_print_parse = false
debug_print_rewritten = false
debug_print_plan = false
debug_pretty_print = false
log_statement = 'all'
log_parser_stats = false
log_planner_stats = false
log_executor_stats = false
log_statement_stats = false
lc_messages = 'en_US' # locale for system error message strings
lc_monetary = 'en_US' # locale for monetary formatting
lc_numeric = 'en_US' # locale for number formatting
lc_time = 'en_US' # locale for time formatting
many thanks in advance !
---------------------------(end of broadcast)---------------------------
TIP 3: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faq
---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?
http://archives.postgresql.org