paging/memory management

[Greg Martin]

Having some memory problems on one of my 11i servers, I was reviewing some doc on hp paging, vhand, etc. I decided to check what minfree, desfree, and lotsfree were set at on my systems. I looked at 4 or more systems, using kmtune, and I was surprised to find all current values as "-".

What does this signify? Paging disabled? Paging parameters somehow dynamically tuned? Some unspecified default value?

[James Murtagh · Accepted solution]

Hi Greg,

It just means they haven't been specifically set and the system uses the default rule to scale them. I think kmtune will simply query either /stand/system and if its not set there checks the master file, /usr/conf/master.d/core-hpux in this case. The memory management paper has a list of the default scaling :

http://www.docs.hp.com/hpux/onlinedocs/os/11i/mem_mgt.html

To find the value from a command run :

# echo lotfree/D|adb /stand/vmunix /dev/kmem

Substitute lotfree for the other values, including gpgslim as you will see from the white paper.

Cheers,

James.

[Greg Martin]

Thanks James. As I suspected, defaults that can be overridden.

Also thanks for the link to the version 1.4 memory whitepaper; I'd just located and printed the 1.3 version, from 1997 - a little out of date maybe!

[Bill Hassell]

All those internal docs about how paging is handled can hurt your brain. The system does a great job at 11i handling paging and the dynamic buffer cache, so the only metric you need is po from vmstat. If these are generally single digits during the busiest periods, you're fine. If you see triple digits for long periods, just double the amount of RAM and you should be fine.