Memory Question.

[Guest_imported]

I am currently running Solaris 7 on an Enterprise 4500 server with 14gb of physical memory and 2gb of swap space. After boot up and all my applications are running I have 11gb of physical memory. As time goes on my physical memory goes down without being released. I get mixed signals because my swap space is currently 11GB free with only 2.8gb used (14gb total instead of 16gb). I know that the swap is a mix of physical memory + the disk (/tmp). So since I have the 11GB of swap free why isn't my physical memory representing at least 9gb free? Also why is the swap only totaling 14gb instead of the 16gb? I have used both vmstat and top to verify the memory. Any ideas, suggestions or comments?

 

[andy171]

I had a similar problem whilst trying to use LSF (Load Sharing Facility). LSF is a program which clusters machines together, and checks to make sure that there are enough resources on a machine before submitting new jobs to them for processing.
However, Solaris uses free memory as a file cache. So if you do a rather large find or run a backup on the server just after booting it, you will notice that the memory gets chew'd up rather quickly as you monitor it. However, memory will be free'd up from the file pages/cache as and when you run applications that require more memory than is free. This is not very helpful if you have applications monitoring the memory and waiting until there is enough free before running the application.

I have found a possible workaround which allows you to enable priority paging, but haven't had a chance to test it yet. Have a read and give it a try if you want :-

http://www.sun.com/sun-on-net/performance/priority_paging.html