Special thanks to:
John Daley
Han Pilmeyer
Octave Orgeron
Udo de Boer
Jeffrey Hummel
Jay Nash
Chris Bryant
Interesting tidbit I learned is that all the parameters in sysconfigtab are
in the man pages! You must know the subsystem of interest, but it lays it
all out.
So for the ipc subsystem:
#man sys_attrs_ipc
Anyway, the best suggestions were...
Suggestion 1:
Compaq support suggested that my ufs hit rate was too low and that is should
increase the size of the ubc (to
ubc-maxpercent=50,vm-ubcseqstartpercent=50). Apparently Advfs volumes (our
Oracle database) uses the ubc, while Ufs volumes do not.
You can calculate your ufs hit rate:
# echo "pd vm_perfsum" | dbx -k /vmunix |grep lookup
warning: Files compiled -g3: parameter values probably wrong
dbx: fatal error: hit EOF on standard input file
vpf_ubclookups = 946451216
vpf_ubclookuphits = 641845047
#
vpf_ubclookuphits = 641845047 / vpf_ubclookups = 946451216 * 100 = 72%
Suggestion 2: Came from a couple of people, with the exclamation that it
works for Oracle servers!!
fifo_do_adaptive=0 (from default 1). I'll probably try it.
Here's the man page on it.
fifo-do-adaptive
A value that enables (1) or disables (0) the pipe code that attempts
to
batch writes to a pipe and deliver the data in a single call to a
reader.
Default value: 1 (enabled)
Suggestion 3:
There are several Oracle patches for performance. We were current, but
it's not a bad place to look.
Suggestion 4:
ssm-threshold =8388608
Suggestion 5:
Make sure your Oracle SGA's are fitting inside shm-max.
Our shm-max=2139095040
ipcs -a
You add all the SEGSZ's. They must be less than shm-max.
Original Post:
> Greetings,
>
> I have a Alphaserver 8200 with 4-433mhz cpu's and 6 gig of ram. This
> machine runs several different oracle databases. I have been modifying
> /etc/sysconfigtab trying to improve performance using the white paper from
> Compaq on large memory machines as an example.
>
> I fear that my /etc/sysconfigtab is making things worse as a large
> percentage of my time is spent in system mode and paging activity seems
> very
> high.
>
vmstat -P and ther stuff deleted.
Received on Thu Mar 14 2002 - 15:02:57 NZDT