My thanks to:
Ian responded with the how to verify RAM+DISK with:
Demand paging (de in vmstat) is the one to check.
I assume Oracle likes to have as much RAM as the database size, so
this would give some idea.
A swap -s will show how much memory (RAM+disk swap) is in use, this
should also show how much more is required (if total used > RAM).
> My question is that I want to add additional memory, but does
someone > have a "rule of thumb" on how much memory to add. I
realize I will
> need additional disk space to add the swap, but that shouldn't
be an > issue.
You will _NOT_ need additional disk space to add the swap! Solaris
is its swap, so the reverse is true, the more RAM you have, the
smaller the disk swap has to be (you're thinking of SunOS).
Andrew responded with Oracle utilization as:
Well, oracle 8 initially runs ora_dbwr_, ora_reco_, ora_ckpt,
ora_smon, ora_lgwr, per instance of the database. Each of these
ususally taks 33mb, around 11mb or so runs in resident memory....
so figure you need at least 60mb of real memory per instance of
oracle, and that is not counting other overhead. You also need to
know how many users are making transactions and the number of
transactions over a period of time. I'm suprise that your machine
is even keeping up with 128m of memory with 3/4 instance. Oracle
8 comes with a pretty good doc on figuring out how much resource
you need. Sorry for such a short reply, but the docs will really
My thanks to both of you for your time and help.
______________________________ Reply Separator _________________________________
Subject: adding additional memory
Author: Mark_Conroy@em.fcnbd.com at Internet
Date: 4/10/98 7:54 AM
Question for the group,
I have a sparc 1000e running Soalris 2.6 with 128m memory. It is a
developmental machine and they are running Oracle 8.0.4. They have
increased the number of oracle instances running on this machine. I
have installed some scripts to gather system statistics daily, and I
have noticed that the machine is doing a lot of paging, and I am sure
this is the result of the additional instances(running 4 instances).
My question is that I want to add additional memory, but does someone
have a "rule of thumb" on how much memory to add. I realize I will
need additional disk space to add the swap, but that shouldn't be an
Any thoughts would be appreciated.
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