[ta1243]

> A long running Linux system uses 100% of its RAM.

How about this server:

             total       used       free     shared    buffers     cached
  Mem:          8106       7646        459          0        149       6815
  -/+ buffers/cache:        681       7424
  Swap:         6228         25       6202

Uptime of 2,105 days - nearly 6 years.

How long does the server have to run to reach 100% of ram?

[bayindirh]

You already maxed it from Kernel's PoV. 8GB of RAM, where 6.8GB is cache. ~700MB is resident and 459 is free because I assume Kernel wants to have some free space to allocate something quite fast.

25MB swap use seems normal for a server which doesn't juggle much tasks, but works on one.

[ta1243]

So not 100% of ram, less than 95%