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Former Member
May 07, 2010 at 08:34 AM

Question about SAP + SLES10 + vSphere and the truth about memory

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Hi,

we are using vSphere and SLES 10 for a SolutionManager 7.0 on MaxDB 7.6.

The system is configured with 2 GB RAM in the VM. The database is configured to use 125000 pages as cache (100000 KB).

Yes, I know the system is configured very small for this usage, but it is a demo system...

But the system is really slow. I can't figure out whats the problem.

The RAM is configured with 2 GB in the VM a "free" in linux shows me that there is 500 MB used for file system chache

total used free shared buffers cached Mem: 2076908 2002704 74204 0 28936 578212 -/+ buffers/cache: 1395556 681352 Swap: 6185016 3037744 3147272

so this shoud be ok, for me it is close to the limit...

But VMware infrastruture client shows me, that there are only 300 MB of the 2GB is used ... but the database should use 1 GB and SAP should use some RAM , too.

So who tells the truth? Where does the RAM goes to if it is not used in VMware? Could this be the performance problem?

An other problem is, that the show dev_io of the database shows me very slow access to the files ...

i.e.

I/O via Device Processes: UNIX Devspace Read avg_read Write avg_write tid name count time count time 28596 /sapdata/SYS/sapdata/DISKD01 6532 0.0294 101 0.2077

But VMWare shows that there is nearly no usage of DISK ... average is shown as 150 KBps...

So again, who tells the truth?

What else could be the problem?

Thank you.

Best regards

Christian