Performance issue in K580 11i with 256MB memory ??

[William Leung]

Does anyone have any performance issue in a K580 machine with 256MB Memory (HP recommended memory), running 32 bit 11i?
I know this is kind-of a dumb question, but I just like explore different ideas to fix a problem.

[kamal_9 · Accepted solution]

HI
can you tell with which database we have having so many k class servers with multiple packages in multiple coustomer sites

[A. Clay Stephenson]

Without knowing what applications you are running or the number of users running said applications this is a lot like asking "Is this hammer big enough?". Having said this, there are very few applications that will run well on an 11.11 box with 256MB of memory.

[William Leung]

Thanks for the responses. I know I need to give more detail about my problem.

I'm basically running a set of applications using some shared memory, some sockets, file I/O, nothing big. There's no database, web server or app server, etc...

I just like to see if 256MB memory is too little for anything.

Thanks.

[A. Clay Stephenson]

The only way to answer that sort of question is ask the machine itself. The best tool for this is Glance. You can load the Trial Version from any Applications CD set. With only 256MB of memory, I suggest that you do not run gpm (the Motif version) but rather the character-based interface version, glance. The GUI would probably distort the very thing you are trying to measure. If you are seeing very low (0 would be good; single-digits acceptable) pageout rates then you have enough memory otherwise you need more. Probably the first thing that I would do is scale back the default 50 dbc_max_pct to no more than 20%. Bear in mind that memory for K-boxes is dirt cheap on the used equipment market or even new from 3rd-party vendors. Bear in mind that memory is often the first bottleneck and that at the very least, your applications would almost certainly benefit from a larger buffer cache than additional memory would make possible.

[Sridhar Bhaskarla]

Hi,

A quick test to see if your system is running out of memory is do 'vmstat 2 20' and observe the 'free' column. Multiply it with 4 and you will get the free memory in KB. If you see it very less and if you see some noticeable number in 'po' constantly then it's most likely that the system is paging out.

To confirm it do 'swapinto -tam' and observe the 'used' column corresponding to the swap devices (lines that start with 'dev'). If it is not 0, then you have the pages swapped out.

By default, the kernel parameter max_dbc_pct is set to 50%. If you didn't change it, then it may be a overkill as you don't have much memory. Set it to 10-15%. That's the best you can do.

-Sri

[Steven E. Protter]

256 MB is barely enough memory to run the OS, let alone any applications.

If you want to do some performance measurement, try this background sar script.

See attachment.

SEP

[William Leung]

Thanks for all the quick responses. That's really helpful.