dump and swap size on hpux 11iv3

[Nappy_1]

We have an hpux11iv3 host with 128GB of memory with 8GB on /dev/vg00/lvol2 as dump and swap.
We have recieved some recommendations about swap and dump size as follows:

- The space on the crash dump device is small
- The space on the savecrash directory (/var/adm/crash) is small
- Estimated Crash Size is about 30GB
- Swap space should be at least 25% of physical memory

I don't think that all these recommendations applies to this host.

1/ I checked /var/adm/crash and i found some old crash files (crash.0, crash.1 ...)
the biggest file is about 1GB so that means that 8GB of dump device is fine. are you OK?

I checked also the output of crashconf -v and I see the following:
Total pages on system: 33504559
Total pages included in dump: 5924155
So what is the appropriate size of the dump device?

2/swapinfo -tam shows that the swap device is 0% used (system is using memory only for swap)

Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 8192 22 8170 0% 0 - 1 /dev/vg00/lvol2
reserve - 8170 -8170
memory 124487 93074 31413 75%
total 132679 101266 31413 76% - 0 -

How can i measure the swap occupancy on my system to decide how much swap space i need?

[Richard Hepworth · Accepted solution]

Hi,

The dump space required depends on how busy your system is and much memory is allocated. At present with 5924155 pages included in the dump (assuming your pagesize is at the default 4KB) your dump space required is approx 23GB. This will change though should you increase the load on the server.

/var/adm/crash does not need to be as large as your dump area as generally the savecrash is compressed.

As a guide you should be looking at giving swap space equal to 25% of system memory.