Skip to Content

Archived discussions are read-only. Learn more about SAP Q&A

Memory limit on iSeries


In note 808607, there is a line:

Extended Memory

In the standard system, the maximum size of the available IBM memory is restricted to 64 GB and this corresponds to a value of 66536 for em/initial_size_MB.

What have people done when they reach this limit of extended memory size of 64GB?

I'm currently running an p570 central system and our EM is currently at 40GB. We expect to hit 64GB before all our rollouts are completed.

Do we need to run additional application servers? Or can we increase physical memory on the box and run multiple instances using up to 64GB?

Any advice, please.

Thanks, Andy.

Former Member
Former Member replied

Hi Andy,

I would go for:

as4/MAXSHR64 = 800 (allow max 200GB)

em/blocksize_KB = 4096


As soon as this above becomes an issue, I would go for:

as4/MAXSHR64 = 800 (allow max 200GB)

em/blocksize_KB = 8192


Why ? Because the higher Blocksize increase the overhead as the smallest piece of memory is then 8MB => the EM untilization will really climb up when changing this parameter .... => you want to double in order to be on the safe site and then you can reduce when you do have experience with the new blocksize

Hope this helps,

Volker Gueldenpfennig, consolut international ag - -

0 View this answer in context

Helpful Answer

Not what you were looking for? View more on this topic or Ask a question