DCE VM set to consume all allocated memory?

[ATrabert]

We have a large DCE customer that we are working with to address some performance issues.  After they increased the VM memory to 32 gbs, their VM team commented that the OS is set to use 100% of allocated memory and requested this to be lowered to 95% leaving 5% free.

As far as I know this is expected behavior and we are not able to modify the DCE servers memory usage/allocation, even through the linux console.  Also I would expect swap memory to cover any overages.

Is this correct, or is there some way in the DCE Linux backend to modify OS memory usage to meet the customers request?

[APC_Steve · Accepted solution]

Hi @ATrabert ,

You're correct, there is no way to change how DCE uses memory. Even if there was a command line option, making such a change would be unsupported. 

You're also correct in that DCE uses swap when all (or most) of the RAM is in use. I can't say that I've ever seen an actual 100% utilization of RAM even once swap is starting to be used. 

Here's an example of the system starting to use swap and although RAM is almost all being used (pretty high actually, there is some (>1g) free. I know in this instance there is not a lot of swap being used but I have seen instances of swap as low as 0.

Mem: 16466292k total, 15502928k used, 
Swap: 2097148k total, 60516k used, 

Steve