Adding memory

[Gerry Tully]

I have an N-440 with 4 processors and 6gb of memory. The swap is set to 9gb of device swap. I was able to acquire another 10gb of memory that I would like to add. I remember that the swap should be equal to or greater than physical memory so my question is, could I get away with adding file system swap or does it have to be device swap?
Thanks

[Sandip Ghosh]

That old theory for swap size is no longer valid. After installation of the memory reduce the swap from 9 GB to 1 GB and look at the utilisation of swap space and accordingly take the action.

Sandip

[sekar parthasarathy]

hi,

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xba1ceea29889d611abdb0090277a778c,00.html

sekar.

[steven Burgess_2]

Hi

You can if you like add filesystem swap. If you set the priority to be equal to device swap then allocation will be performed in a round robin fashion

HTH

Steve

[steven Burgess_2 · Accepted solution]

Hi Gerry

Here is an excellent thread with regard to swap space. Replies are from the most respected forumers

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x9d7b42308663d611abdb0090277a778c,00.html

HTH

Steve

[doug hosking]

Not directly related to your question, but you might want to consider that crash dumps are often written to the swap areas. Depending on whether you care about them, you might have to allocate some space even though you wouldn't need it for swap space.

This was one of the original reasons for the '>= physical memory' mandate. But that was before selective crash dumps and many other changes in HP-UX. As previously noted, some of the historical rules are either less relevant or not relevant at all today.

Of course, you should also think about just how long it would take to take and save a crash dump of that size, whether you have enough free disk space to make a permanent copy from the copy written to the swap area, etc.

[T G Manikandan]

If you have 16GB of memory of machine are there programs which use more than the amount.
It is not that you should have 1:2 memory to swap or 1:1 memory:swap

If you see that having 16GB of RAM and there is no swapping happening in the first place there is no need to add any swap to the existing 9GB.Infact you can reduce them to 500MB.
When that is the case then you can enable the pseudo-swap(swapmem_on=1) in the kernel.
When there is not swapping happening on the system then who cares about the device swap.
Also,If I am have a mirrored disk then there is a lot of space unused on the mirror disk which is a waste.