Linux

Hi,

Yersterday I started monitoring my homeserver memory consumition due some errors found in the system (network hangs). I've detected almost all the memory used (~10 MB free from 1GB).

First I thought it was because of the MySQL configuration, so I monitored it with top and found it wasn't (I've checked the config file too, a home server doesn't need very large databases ).

I was not sure and I stopped about what was happening and decided to stop processes in the system. I finaly stopped all server processes and still find about 800 MB of RAM memory in use. Top knows they're in use but doesn't know what is using them exactly.

Where can I start to search?

Thanks in advance

Linux? What's "free" say? It's probably all just used in cache/buffer

Hi,

I mean to say available. I know, but 800 MB is a lot!! isn't it? I think something should be wrong somewhere...

---------- Post updated at 08:20 PM ---------- Previous update was at 08:16 PM ----------

Ah, and Debian Linux Squeeze with custom 2.6.39 kernel (compiled from Debian source)

Code:

[mute@geek ~]$ free
             total       used       free     shared    buffers     cached
Mem:        255636     239268      16368          0      57724      97476
-/+ buffers/cache:      84068     171568
Swap:       262136      40868     221268

Let's see this output first... See, even though my processes only take up about 83MB, there is only about 13MB free of 256MB.. That's because the kernel will cache and buffer things...

What do you think it should be doing with it? Unused memory just sits there, wasted, so it uses as much for cache as is available. It gives it up as easily as 'free' memory so it doesn't hurt anything.

Thank you neutronscott, here it is. ~750 MB cached...

Code:

nefeli@currante:~$ free
                   total         used         free    shared    buffers     cached
Mem:       1024880    1005860      19020           0    119432     790400
-/+ buffers/cache:       96028     928852
Swap:      3903788        1208    3902580

I suddenly started to have problem with the system managing the huge NAT table from aMule connections and making the system hang temporaly the network interface. I never had this problem before and I'm trying to find the reason. I've found the kernel tcp_max_syn_backlog unusualy low, so I thought that the problem was the free memory.

This command may help you see what your system is doing (it is a bit better than "free" in my opinion)

Code:

vmstat -s -S M | egrep 'mem|swap'