question about memory usage in linux
torriem at chem.byu.edu
Tue Nov 22 11:37:11 MST 2005
On Tue, 2005-11-22 at 10:13 -0700, Gregory Hill wrote:
> Excuse my ignorance again, but where do you get the 10MB swap figure for
> Apache and 20MB figure for mysql? Is that in top, but I just don't see
> it? Anyway, I'll keep watching it to see if I can find a pattern. The
> problem is it usually crashes at night, when I'm asleep. My guess is
> still a mod_perl leak, but for some reason it only occurs during the
> night. Does anyone know a good memory monitoring script that can email
> me details at a certain threshold? I'll write my own if not, but if
> there's something already out there, I'd love to save the hassle.
I got the approximate figures from your ps output. I've deleted that
message now, but I basically took the vsz column (total virtual memory
size) and subtracted the resident size column from it.
Top does indeed show this kind of thing. Not sure if top has changed
since RH9, but FC1, top shows the following headings by default:
PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU
11365 root 16 0 29268 23M 8768 S 0.0 1.1 1:27 0 spamd
12098 root 18 0 28744 22M 8532 S 0.0 1.1 1:52 0 spamd
12087 root 16 0 28768 22M 8436 S 0.0 1.1 1:23 0 spamd
20823 root 17 0 27748 22M 8272 S 0.0 1.1 2:45 0 spamd
20871 root 19 0 28432 21M 7908 S 0.0 1.0 2:23 0 spamd
4095 defang 18 0 16876 16M 2036 S 0.0 0.8 0:01 0
RSS field is the "resident size" or the programs current physical ram
use (if this ever falls below the program's working set, then you get
thrashing). The SIZE field (VSIZE on FC3) indicates the total memory
use, which is really swap+resident. SHARE means shared memory, but that
can't be counted against the totals.
I'm sure that there are scripts that exist, but I don't know of any
> Thanks for all the input.
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Michael Torrie <torriem at chem.byu.edu>
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