Oracle Opinion

[Jim Mallett]

Just looking for some feedback/opinions on memory.
I'm administering a couple of L2000 servers (one is running 11.00, the other 11.11). The main use for both of them is Oracle. The are both running 3 database instances (one of which is Financials).
Also, both machines have 4G of memory. Lately I have been experiencing more and more memory related issues. ie: processes like midaemon getting killed

Is 4G enough? I've read that 4G would be the minimum for this type of enviroment.

Any thoughts?

[John Poff]

Hi,

If you are running Oracle 8 and Financials, you could use more memory as they are both big memory hogs. We are running a big Financials database here and we have 12 Gb of RAM on the system.

How much memory are you using on average on the boxes?

JP

[Ken Hubnik_2]

It depends on how big the DBA's are using for the Oracle SGA. Whatever is left over after the SGA gets carved out is left the the rest of the system.

[Stefan Farrelly]

We run many L class servers with more than 3 oracle instances on them (some 6+) and they run fine with only 2-3Gb of RAM. It all depends on your SGA size for Oracle. Does each server have free memory ? (ie. you never run out of free ram) vmstat will show you (free column*4096).

Even if you do run out of memory there is no way system processes should start dying. midaemon dying is a known bug - plenty of patches/new version to fix this. Were running the latest version and its stable as a rock (Glance product). If you do have processes dying you need to look at each on an individual case.

[Sridhar Bhaskarla]

Hi Jim,

Install glance, if you haven't already, and see how much memory is being used. If there is no free memory, the system will start paging and degrade the performance but haven't heard killing the processes.

Also get your dbc_max_pct to around 8%. Using the default value of 50% is not worth it.

-Sri

[Jim Mallett]

Glance is installed, unfortunately at some point yesterday the midaemon was killed so I can't run it right now.
/opt/perf/bin/midaemon: Wed Dec 4 12:08:40 2002
mi_create - Shared Memory Database initialization failed; vss = 15695200 bytes
Not enough space

I believe all the databases are set around 750M, I have shmmax set at 786432000. The Oracle admin said something about the databases will "double up" and use 1.5G.

Memory and Oracle is not my forte (yet).

min/max dbpct is set at 5/10.

Thanks for the quick responses.

[S.K. Chan]

I've seen the glance error before, in my case I upgrade my glance to the latest version and the problem went away. What version of glance are you running on your 11.x ?

[Jim Mallett]

Wow, I patch my system every couple months but I've been overlooking my Glance update.
Didn't realize I was so far behind. Thanks....

Attached is a VMSTAT output. There isn't any Paging IN/OUT going on but a lot of Faults.