11i upgrade - memory overhead

[Ian Foster]

We are about to upgrade our N class 9000 production server from HP-UX 11.00 to 11i.

I have read that there is an increase in system overhead for this upgrade, particularly for memory.

Can anybody in HP land quantify this overhead or increase (even a ball-park figure would be appreciated).

We have something in the order of 8Gb of physical memory in the system and do not really anticipate this being an issue but I would like to have a better idea of the nature of this increase.

[Mike Fisher_5 · Accepted solution]

Hi Ian

I was researching a similar question recently

I found this thread got me going along the right path

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x0a3ceea29889d611abdb0090277a778c,00.html

Have you tried searching this forum?
keywords such as:
upgrade, 11i, memory

Produces LOADS of results

Happy Friday
Mike

[Steven E. Protter]

I have read in the trade publications that the minimum amount of memory you want to run a production environment on 11i is 2 Gig.

I've played around with 1 Gig systems with 2 Gig of swap and it does work, but the workload you can get out of those machines is less than the same machines on 11.00.

My work was on D class servers. N Class does have a faster cpu and might have better results.

SEP

[A. Clay Stephenson]

This is one of those "it depends" answers. The only time I've found that more memory was really needed for 11.11 is boxes (like little A180's with about 256MB; in that case increasing to 512MB really helps). I've found that typically the OS memory requirements increase by something like 60-100MB - no big deal if you have lots of memory but if you start with 256MB then it is a big deal.

The other big difference is that typically optimum buffer cache on 11.0 was somewhere around 400MB; on 11.11 anywhere from 800MB to 1200MB is optimum.

From these two observations, if you now have 500-600MB free under 11.0, you will be fine under 11.11.

Finally (and this could be the big one), if you were running Oracle raw disk (or the OnlineJFS equivalent convsync=direct,mincache=direct), you will find that Oracle does better under 11.11 with "cooked" files; if you intentionally had limited buffer cache to allow larger SGA's then you could need more memory.