From: Andy Pavitt (a.pavitt@ntlworld.com)
Date: Sat Nov 30 2002 - 09:45:17 EST
Tru64/Oracle Gurus, please can I pick your brains.
Tru64 UNIX V5.1A Patch kit 3
4 x ES45's clustered
Oracle 9i RAC
We are currently testing our Oracle 9i RAC on our 4 node ES45 cluster
and are
experiencing strange performance behaviour.
For example, When we setup one node in the cluster as a
bog standard non RAC single instance, performance is fantastic.
Yet, on a 2 - 4 node RAC cluster Oracle DB performance is crap.
After much monitoring of the cluster performance, we are convinced all
oracle traffic is going via the network interfaces instead of via
the memory channel.
If we run monitor on each node, then kick of our tests, the traffic over
the network interface increases massively, then when we stop our tests
things return to normal.
A couple of questions, how does oracle make use of the memory channel ?
Ive looked at the RDG man pages, not too much to be gleaned here.
How can I monitor oracle specific traffic across the memory channel ?
Ive written this little script below to gather stats, but interpreting
the output is the problem.
How can I determine from the stats what is related to oracle ?
Is there any decent documentation to assist me in understanding what
the output of the stats is telling me, more indepth info on "imcs" and
"cfsstat"
Ive trawled the web, HP/Compaq and oracles web site
looking for more info on how oracle uses the Memory channel interconnect
but have come up against tons of marketing blurb and nothing else.
Any help greatly appreciated
Andy
#!/bin/ksh
PATH=/usr/bin:/usr/sbin
export PATH
E="echo"
FILE=/var/adm/sa/${HOST}_IMC_MC_STATS
FILE2=/var/adm/sa/${HOST}_CFSSTAT_STATS
FILE3=/var/adm/sa/${HOST}_RDG_STATS
HOST=`netstat -i | grep -i ics | grep -i livedb | awk '{print $4}'`
DT=`/sbin/date +%d-%m-%y-%H:%M`
$E "IMCS Memory channel stats for ${HOST}" > ${FILE}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE}_${DT}
$E "CFSSTAT Memory channel stats for ${HOST}" > ${FILE2}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE2}_${DT}
$E "RDG stats for ${HOST}" > ${FILE3}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE3}_${DT}
/usr/sbin/imc_init
while true
do
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE}_${DT}
/bin/date >> ${FILE}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE}_${DT}
/usr/sbin/imcs >> ${FILE}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE2}_${DT}
/bin/date >> ${FILE2}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE2}_${DT}
/usr/bin/cfsstat >> ${FILE2}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE3}_${DT}
/bin/date >> ${FILE3}_${DT}
$E "+++++++++++++++++++++++++++++++++++++++++" >> ${FILE3}_${DT}
/sbin/sysconfig -q rdg | grep bytes >> ${FILE3}_${DT}
sleep 3
done
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