swap space inside a vmware virtual machine recommended?

[Former Member]

Hello experts,

we have SAP (ECC 6.0) Test and Dev running in virtual machines (server 2003, 64-bit, the db is running on a seperate physical linux RAQ cluster) and are planning the Prod system to be running in vmware too.

The official recomendation for swap space is 1 x RAM plus 8GB. That would result in a very large swap file that would lie on the EVA storage. Now people in HP are saying that they do not recomment large swap files on the (shared) storage because this would seriously slow down the other systems that are also running on the EVA.

My question is, if one of you has some real-world expirience with running SAP in Prod inside a vmware virtual machine and if you've found any issues with the use of large swap files?

Why does SAP need those large swap files if it has got enough physical memory??

Are there any best practices that I am not aware of?

thanks for your help

[markus_doehr2]

> My question is, if one of you has some real-world expirience with running SAP in Prod inside a vmware virtual machine and if you've found any issues with the use of large swap files?

>

> Why does SAP need those large swap files if it has got enough physical memory??

Linux sees physical memory and swap space as a "whole" big memory. Uusally 20 GB is enough for a 64bit application server. The memory is used to create big shared memory segments at the application start. It's done that way because shared memory can't "grow", it's allocated once at the system start.

Markus

[Former Member]

planning the Prod system to be running in vmware too.

Check database and SAP combination is supported with vmware.

The official recomendation for swap space is 1 x RAM plus 8GB

Not sure where this is coming from but usually application like ERP we use 3 to 4 times of your RAM.

Why does SAP need those large swap files if it has got enough physical memory??

I would suggest you to go through SAP memory management. There are loads of documents on net. just google it and you will find lot of documents.

Hope this helps.