HP-UX on Integrity Memory Configuration Guideline

[Andy Bustamante]

I have HP-UX (11.23) on an Integrity 4640 server with 8 GB installed. Memory is installed in 16 x 512mb running an Oracle database.

The system is pushing memory limits and I'm researching upgrade options. Are there memory interleave guidelines on this server similiar to the ES 40/45 Alphaservers? On those servers , HP/Compaq strongly recommended symmetrical memory options in powers of two to maximize access speed.

For example, if I upgrade to 32 GB would the server have faster memory access times with 16 x 2GB or can I use 8 x 4GB and still leave room for future expansion?

Andy Bustamante

[Rita C Workman]

Andy,

Have you done any kernel parm tuning yet?
Maybe before upgrading hardware, let's see if possibly some performance tuning might be appropriate.

What version of Oracle?
List of kernel parms....

Just a thought,
Rita

[Steven E. Protter]

Shalom,

I'm almost certain based on experience swapping to different memory chips will not make a difference to Oracle performance.

If you need memory, I'd leave room for expansion because Oracle is a memory hungry monster and that is unlikely to change.

The single best way to deal with a system pushing memory limits it to buy more memory. You can do that with confidence.

By all means get the fastest memory you can buy, get it from HP, but this choice does not require a lot of deliberation. I always like to have expansion room in a system.

SEP

[Duncan Edmonstone · Accepted solution]

Andy,

Well the rx4640 supports 2 different memory carrier boards:

A9738Aâ Supports from 4 to 16 DIMMs
A9739Aâ Supports from 4 to 32 DIMMs

But both have the same memory bandwidth to CPU (12.8 GB/s) and the way memory is loaded (in quads of DIMMs and in certain orders on the memory conmtroller), its pretty difficult to configure the memory in anything but a non-optimal configuration.

So the first thing to do is determine what carrier board you have to make sure you can upgrade without replacing the memory carrier... but as for your original question, beacuse of the way memory is loaded, as long as you follow the memory loading rules, then the 8x4GB will be fine. Rules are:

-Memory must be installed in groups of four DIMMs, also known as quads
-Each quad must consist of equal density DIMMs
-Memory can be ordered in quads of 1 GB (4Ã 256MB), 2 GB (4Ã 512MB), 4 GB (4Ã 1GB), 8 GB (4Ã 2GB), or 16 GB (4Ã 4GB)
-Minimum memory is 1 GB (4Ã 256MB)
-Maximum memory is 128 GB, using eight 16-GB memory quads in memory carrier board A9739A
-Memory must be loaded in the order depicted on the memory carrier board
-Arrange DIMMs so that the quads with the largest capacity are in the lowest numbered slots.

HTH

Duncan

[Andy Bustamante]

Thank you.

Duncan, I have the 16 DIMM memory carrier board with 16 x 512mb installed.

If I replace 8 of the 512mb DIMMS with 4GB that would give (8 x 4GB + 8 x 512mb) = 34GB of installed memory. Or would I be better off with 8 x 4GB for 32 GB?

DBA and an system admin are reviewing tuning options but don't expect to change the recommendation to add memory.

Side note: Configuring this system requires a DIMM or air flow filler in the slot for proper cooling.

Andy

[Andy Bustamante]

HP Reports on this class of system there are no additional guidelines. Cell based Integrity servers do have additional memory configuration guides.


Andy Bustamante