How my HP-UX system utilize the RAM installed?

[Loi Luca]

Thanks

I have upgraded my HP-UX system at 2.0 GB

the SAM Utility and cstm reporting the correct installation of RAM.

the TOP utility reporting the following information:
Memory:674700K(variableK) real, 312776 (variableK) virtual, 28196K free.

The report is correct? the utilization of memory is comprehensive of new RAM?

My memory free (variable) remaining extremely low.

Help me.

Thanks

Loi Luca

[Steven E. Protter]

HP-UX defines memorhy as RAM plust swap. Several utilities report it this way. SAM and cstm are being asked to report RAM and therefore report the way they do.

Answer: both are correct based on how they were designed.

Run: swapinfo -tam

You will see swap allocation.

vmstat will let you know if you are paging to swap.

SEP

[Eric Antunes]

Hi,

The memory between parenthesis is the current active. You can compare this top info. with the SAM info. (SAM -> Performance Monitors -> System Properties -> Memory)

About vmstat, explore the -dnS options:

#vmstat -dnS 5 100

Best Regards,

Eric Antunes

[Loi Luca]

Thanks you Steven

My really problem is the connection with server in ODBC mode with a DBMS Oracle by multiple clients.

The probles NOT IN Oracle (unlimited license).

My observation of activity server have this result:
IF the result of the memory free with TOP utility > 10400Kb connection successful
IF the result < 10400Kb (memory free) conncection failed.
The size of single process allocated by application is 4000/8000 Kb

the result of swapinfo -tam in this moment (server in low activity and 28846kb free at TOP utility) is:

TYPE AVAIL USED FREE USED LIMIT RESERVE
dev 2048 0 2048 0%
Reserve - 1600 -1600
memory 1508 955 553 63%
total 3556 2555 1001 72%

The result of Vmstat -dnS 5 100 is (in this moment):

minimum

avm free
17000 7128

maximum

avm free
21000 7128


Thanks you very much

Luca Loi

[Geoff Wild]

Looks fine to me.

If you want have another view, try compiling the following c program called memdetail

Output like:

# memdetail
Memory Stat total used avail %used
physical 10080.0 9809.6 270.4 97%
active virtual 11309.4 4779.4 6530.0 42%
active real 7361.7 2971.1 4390.6 40%
memory swap 7693.0 1546.9 6146.0 20%
device swap 26528.0 10890.6 15637.4 41%


Rgds...Geoff

[Sanjay_6]

Hi Loi,

Maybe this link from itrc would help you dig deeper into the cause of memory usage.

http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000076088045

The itrc doc id is KBRC00011764.

hope this helps.

Regds

[Bill Hassell]

You have somewhat low RAM for a large Oracle application (4Gb is more useful). However, since you added RAM, the amount of buffer cache went up to 1000megs unless you changed the kernel parameter dbc_max_pct to something 15-20 (percent). But since you are getting the error message and swapspace appears to not be in use, you probably have plenty of RAM and you are getting a programming error due to 32bit limitations. 32bit programs are severely constrained as to how they can use large amounts of RAM. The amount of free RAM in vmstat is not very meaningful because HP-UX will start to pageout when necessary.

It's not just the program's data area (local memory), but shared memory. Oracle (and other middleware programs) use shared memory that has similar limitations as a 32bit program. Use the command: ipcs -bmop

This will tell you how many segments are in use and what size they are. If the list is long, you probably have shared memory segments that have become 'orphans', especially if you use the (dreaded) kill -9 command. A reboot will fix this problem. It's quite difficult to determine whether a shared memory segment can be removed. Also, shared memory is always subject to fragmentation where there are many small chunks but no big chunks. If a program wants a big chunk, it will get a memory error because the contigous section of memory is not available.