HP-UX 11 64-bit memory use

[Jon Talbot]

If I load my J6000 with the max 16GB RAM what is the maximum memory that a single process can access? Nb. it is built with HP-UX 11.00 64-bit.
Thanks, Gary.

[Tim Sanko]

That depends on a whole host of things including tunable parameters. Post your /stand/system, and I can tell you.

It is really addressed in the kernel configuration.

Tim

[A. Clay Stephenson · Accepted solution]

Assuming that your have maxdsiz_64bit and shmmax set very large; your can actually exceed your 16MB physical RAM. In this case you would be limited by the amount of virtual memory (RAM + swap)that is
configured. Of course, if your start using that much memory, the box
will
be a dog so the practical answer to your question is determined by maxdsiz (maxdsiz_64bit), shmmax, and to a lesser extent
maxtsiz, and maxssiz.

In practice, you would not set the maxdsiz that big precisely so that no one rogue process can grab all the resources in sight.

[Tim Sanko]

In fact, it really depends on your applications also... Oracle eats up HUGE amounts of memory.

He mentioned the offending/responsible parameters, but I recommend using SAR to get parms about the processes utilizing RAM too.

I don't stop at RAM+SWAP.

I try to take a good look at applications and place greedy ones on filesystems without largefile capability.... If they don't need to make over a 2GB file....


Tim