MAXDB Configuration Tips

[Former Member]

Hi,

I need some tips (if it is possible...)

1- I have a server with 2 quad-core processors. What should be the best value for MAX_CPU?

(the server works only for database, no other service is installed)

2- It has 5Gb of RAM.

My CACHE configuration is :

CAT_CACHE_SUPPLY int 48625

CACHE_SIZE int 388998 (3Gb)

Is this a good confioguration ?

4- In order to use 5Gb, I had to use a 64bit OS (Suse linux 10.3) and MAxdb 64Bits...Just for info...

Thank you very much for your attention,

[lbreddemann · Accepted solution]

Hi Daniel,

two quad-core CPUs make up 8 cores.

If your server should do nothing else then MAXCPU=8 will enable 8 parallel threads for user tasks.

5 GB Ram is not very much for a database server.

What should the DB be used for?

CAT_CACHE_SUPPLY - don't do anything with this parameter. It won't really pay off. Why do you want to put 380 MB just for the DB catalog cache?

Any indication for that?

How many sessions/usertasks do the instance see at any given time?

Better: put as much mem to the CACHE as possible. 3 GB is nice - 4 will be better.

> Is this a good confioguration ?

Good for what?

> 4- In order to use 5Gb, I had to use a 64bit OS (Suse linux 10.3) and MAxdb 64Bits...Just for info...

Sure you're using 64-Bit. It's not your playaround, laptop database is it? So if you're in serious, high volume database usage, you'll use 64-Bits nowadays

Anyhow, much more interesting than the Memory/CPU setup would be your storage layout.

Usually neither CPU or memory are the bottlenecks for DB systems - CPU is cheap today, RAM is cheap today.

Fast I/O on the other hand - not cheap, really not.

Whatever you have there, make sure to avoid using os-filesystem-buffering (USE_DIRECTIO=YES) and to set SIMULATE_VECTORIO=NEVER.

Also: no REDOs on RAID-5 and make sure to have multiple data volumes of the same size.

regards,

Lars

[Former Member · Accepted solution]

HI Lars,

The DB is used to provide data to OLTP system. It is a healthcare system.

I read in the net (in old MYSQL/MAXDB forum) the following :

Cat_cache_supply = 25% cache size

cache_size = 75% ram thats why I changed the original value.

200 User Sessions

Good for a dedicated DB server.No other service is running.

Thank you very much for your help !!!

[lbreddemann · Accepted solution]

Hi Daniel,

if the CAT_CACHE_SUPPLY is not sufficient for all sessions than MaxDB will take some space from the datacache for it. So it's pretty hard to really undersize it.

Concerning the MaxDB Version (we already had this discussion didn't we?):

Tell your vendor to come up with some reasons for using a terribly outdated version of MaxDB for which nobody will deliver any support (except the recommendation to install the current patch)!

regards,

Lars

[Former Member · Accepted solution]

Yes we had it and you are rgiht.

To solve the problem I asked my client to open a support ticket regarding this issue.

I did not understand why they asked for this specific version.

Best regards and thank you very much,

[former_member229109]

Hello Daniel Castro,

1) Are you SAP customer?

If you are SAP customer, you have access to SAP notes.

=> Please overview the SAP notes:

1173395 FAQ: MaxDB configuration

936058 FAQ: MaxDB Runtime Environment

< Pay attention to the answer on the question "12. Which factors determine how the MAXCPU parameter is set?" >

1111426 Parameter check for liveCache/MaxDB instances

2) Please post the version of the database and database type.

Please see information at http://maxdb.sap.com/doc/7_7/default.htm -> Glossary

-> Database Parameter -> MaxCPUs < MAXCPU >

3) In general if you have 2 cores CPU on the database server and the computer is used purely as a database server, MAXCPU (as of Version 7.7., this is MaxCPUs) recommended to set to the number of CPUs, e.g 2.

Thank you and best regards, Natalia Khlopina

[Former Member]

Hi Natalia,

1) Unfortunately not.

2) Database Version : 7.6.00.27 (required by the ERP manufacturer) OLTP 64 bit. MAX_CPU=2

Best regards,