Is 2G RAM all used really Normal?

FredJones · 08-06-2008, 02:30 PM

I have a client with a RedHat dedicated server and I ran top today via ssh and saw that almost all of his 2G was being used. Also I saw some 20 httpd processes with zero percent CPU usage. I thought this was odd. There is only one site on this server and usually (when I have run top in the past here and there) it's well under 1G RAM used.

So I called support and he said that as long as the Swap space is not being used up, then it's normal and nothing to worry about. He said this:

Code:

[root@lnn826 ~]# free -m
             total       used       free     shared    buffers     cached
Mem:          2026       1937         89          0         75        638
-/+ buffers/cache:       1223        803
Swap:         2047        102       1944

is fine. Here is top after I press M to sort by RAM:

Code:

top - 14:28:39 up 286 days, 10:04,  1 user,  load average: 0.35, 0.34, 0.30
Tasks: 123 total,   1 running, 122 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.3%us,  0.3%sy,  0.0%ni, 85.9%id, 13.6%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   2075516k total,  1985188k used,    90328k free,    75696k buffers
Swap:  2096472k total,   104996k used,  1991476k free,   652404k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 2110 apache    15   0 70004  47m 5816 S    0  2.3   0:50.73 httpd
 1064 apache    15   0 70048  47m 5724 S    0  2.3   0:31.64 httpd
 6431 apache    15   0 69700  47m 5788 S    0  2.3   0:23.30 httpd
 2694 apache    15   0 70056  46m 5148 S    0  2.3   0:54.79 httpd
 2046 apache    15   0 69188  46m 5820 S    0  2.3   0:28.99 httpd
 1065 apache    15   0 69848  46m 5068 S    0  2.3   0:26.22 httpd
 1059 apache    15   0 69704  46m 5192 S    0  2.3   0:55.42 httpd
 2696 apache    15   0 69604  46m 5160 S    0  2.3   0:25.39 httpd
 6432 apache    17   0 68912  46m 5696 S    0  2.3   0:36.65 httpd
 1063 apache    15   0 68924  45m 5228 S    0  2.3   0:43.63 httpd
 2685 apache    16   0 68988  45m 5120 S    0  2.3   0:25.98 httpd
 2697 apache    15   0 68956  45m 5112 S    0  2.3   0:22.78 httpd
 2627 apache    15   0 68772  45m 5280 S    0  2.3   0:23.79 httpd
 2605 apache    15   0 68516  45m 5224 S    0  2.2   0:36.49 httpd
 2615 apache    15   0 67864  45m 5684 S    0  2.2   0:39.37 httpd
 2617 apache    15   0 67436  44m 5844 S    0  2.2   1:06.41 httpd
 2643 apache    15   0 67924  44m 5192 S    0  2.2   0:34.87 httpd

He said this too is normal.

Can anyone confirm or deny this? It seems a bit odd to me.

Thanks!

trickykid · 08-06-2008, 02:31 PM

Yup, Linux utilizes memory. Notice the amount cached. Linux is not Windows, it actually uses the RAM available. Think of it this way, what's the point of having 2GB of RAM if only 1GB is used at any given time, you might as well only install 1GB of RAM if that's all the system uses, etc?

FredJones · 08-06-2008, 02:50 PM

OK, thank you.