Virtual memory

[M. Tariq Ayub]

Hi,

as i know virtual memory = physical memory + swap space.

is there any way to configurable parameter that increase VM

[Mark Grant]

You can add more swap by making a contiguous logical volume and doing a "swapon and you can also install more physical RAM. You can reduce the buffer chache size too as it's a kernel tunable but I wouldn't be playing around with that kind of thing if all that is happening is you are running out of VM. The proper solution is buy more RAM.

[Elmar P. Kolkman]

/usr/sbin/swapon is what you need, I guess... Can be done runtime.
Or you need to shutdown, add (physical) memory (RAM) and boot again.

[Leif Halvarsson_2]

Hi,
There is several ways to increase virtual memory (reinstall the OS and increase swap space, create an additional swap volume etc.). But, do you really need additional swap space. If your system begins swap data on disk it will have a big impact on system performance. A much better way is to increase memory.

[M. Tariq Ayub]

Hi,

i have 3 GB physical memory and 4 GB swap so my total VM should be 7 GB. Gut in glance i saw that total vm is only 700 MBand used is 600 MB.

How can my total vm only 700 MB

Total VM : 696.7mb Sys Mem : 423.7mb User Mem: 412.0mb Phys Mem: 3.00gb
Active VM: 532.1mb Buf Cache: 1.50gb Free Mem: 700.2mb

[James Murtagh · Accepted solution]

Hi Tariq,

What Glance is reporting is the memory regions allocated to the VM subsystem. This figure will include, among other things, the total of the pages demand loaded and hence in the page cache, including shared libraries, executables etc. The difference in the active VM may be pages in the page cache but on the free list. I think the swapinfo command may show you the figures you want to see - you can increase the total "VM" figure by setting the kernel parameter swapmem_on to 1, or by adding more swap space as has been suggested. If you want to find out more about these and related subjects, the memory management white paper has most of the answers, although it's not exactly bedtime reading shall we say. :-)

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

Also, note you can use the tooltip in Glance to find out what each of the headings are actually reporting.

Cheers,

James.