Hi,

In one of RHEL5 server I am facing low memory problem.

While checking /proc/meminfo i got below o/p

MemTotal: 16410952 kB
MemFree: 45332 kB
Buffers: 106252 kB
Cached: 15236112 kB


Any idea which process is utilizing high cached part of memory.

O/P of top is as below.

top - 06:18:07 up 71 days, 17:24, 10 users, load average: 6.83, 8.29, 12.12
Tasks: 211 total, 6 running, 202 sleeping, 0 stopped, 3 zombie
Cpu(s): 33.3% us, 33.3% sy, 0.0% ni, 0.0% id, 0.0% wa, 0.0% hi, 33.3% si
Mem: 16410952k total, 16360452k used, 50500k free, 107432k buffers
Swap: 16777208k total, 269756k used, 16507452k free, 15221532k cached

Cache isn't associated with a process per se, it is related to I/O on your system.

Linux tries to cache as much I/O data as it can. If that data needs to be read in the future, it is already in storage. Cache is a mechanism to avoid doing real I/O operations as real I/O to a disk is very slow compared to just retrieving it from memory. So a high cache number is generally good and nothing to be concerned with.

If on the other hand your cache has been trimmed back and is now very small and you start using a lot of swap, then you have a low memory problem.

One caveat is that caching data works very well if the memory is real memory (you're running on bare metal). If this is a virtual system, that memory is virtual memory provided by the hipervisor and the hipervisor may end up swapping... Not a good thing.

Your load average looks high.