Slow performance inside a Windows-VM

[Former Member]

We have several (3) Windows 2003 x64 Systems working on top of a 8gig quad-core machine.

The Systems are only for testing and evaluation and are being used only by a few (ca. 4) users.

If the systems are booted up everything is very slow because of the enormous memory and pagefile usage of oracle and sap.

How can we change the memory usage of every SAP instance and also the oracle databases which are also installed inside the virtual machines?

Regards.

Alex

[markus_doehr2]

What virtualization do you use? VMWare ESX?

Markus

[Former Member]

Vmware Server 1.04 on Centos Linux on an AMD Phenom 9500, 8gig RAM, 4x400GB Raid 10 Sata.

I know, its not enterprise. But these systems are only for evaluation and self-teaching...

[markus_doehr2]

ًWell...

VMWare Server does not really "virtualize" but emulates a full metal system. Due to the fact, that also the disks are "virtualized" (means, you create a virtual disk on an already filesystem) and due to the fact, that it doesn't use the virtualization capacities of the CPU it is slow by definition.

There's not much you can do about it aside from using a different virtualization system.

Markus

[markus_doehr2]

And maybe as additional info:

If you use CentOS to host the system, you could upgrade to CentOS 5.1 and use XEN as virtualization software instead of VMware and install your instances paravirtualized on Linux...

Markus

[Former Member]

Thanks for your reply. I already tried XEN virtualization on the AMD X64 CPU but failed to start the Windows boot-cd.

[markus_doehr2]

Full virtualized system are always slower than bare bone systems (or paravirtualized).

I suggest to use either VMWare ESX Server or install Linux (instead of Windows) as paravirtualized system.

Markus

[Former Member]

Hi Ciric,

Is this Java or ABAP? on either case, 3 systems with its own database on a 8 GB machine and 4 cores it is too much, do you really need 3 systems, 1 system can be share by your four users.

To reduce the memory used by Oracle you can adjust the following parameters:

db_cache_size

sga_max_size

shared_pool_reserved_size

shared_pool_size

Those mentioned before are only the most common.

Zareh