managing memory usage

[Joe Woltering <jw...@hamptons.com>]

Hi,

I'm running Spamassassin 3.0.4 on a Dell Poweredge 750 with 2.8 Ghx CPU and
2 Gb of RAM. I have configured it with amavisd-new, clamd, dccifd, razor and
pyzor. We're handling approximately 225 domains w/ app. 5000-6000 users.

Everything is running great w/ the exception that the memory seems to keep
growing. On boot-up it seems to startup around ~500Mb and stay there for a
bit but then slowly starts to creep up and never looks back. In about 24
hours it grows almost to the full 2Gb. Right now it's at 1.8.
Should I be concerned?, or is this normal operation. I realize that a lot of
this is cached memory. Will this memory be freed up if other system
processes require it. I'd rather not have to dip in to the swap. Here's an
output of my current 'meminfo':

MemTotal:              2074708 kB
MemFree:               235392 kB
Buffers:                  184128 kB
Cached:                 1125232 kB
SwapCached:         0 kB
Active:                   797356 kB
Inactive:                 778772 kB
HighTotal:              1179392 kB
HighFree:               620 kB
LowTotal:               895316 kB
LowFree:                234772 kB
SwapTotal:             2031608 kB
SwapFree:              2031608 kB
Dirty:                     10568 kB
Writeback:             300 kB
Mapped:                 284932 kB
Slab:                      244452 kB
CommitLimit:          3068960 kB
Committed_AS:      597560 kB
PageTables:           7304 kB
VmallocTotal:         114680 kB
VmallocUsed:         3824 kB
VmallocChunk:       107736 kB
HugePages_Total:     0
HugePages_Free:      0
Hugepagesize:         2048 kB
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Re: managing memory usage

[Matt Kettler <mk...@comcast.net>]

At 09:57 AM 7/29/2005, Joe Woltering wrote:
>I'm running Spamassassin 3.0.4 on a Dell Poweredge 750 with 2.8 Ghx CPU 
>and 2 Gb of RAM. I have configured it with amavisd-new, clamd, dccifd, 
>razor and pyzor. We're handling approximately 225 domains w/ app. 
>5000-6000 users.
>
>Everything is running great w/ the exception that the memory seems to keep 
>growing. On boot-up it seems to startup around ~500Mb and stay there for a 
>bit but then slowly starts to creep up and never looks back. In about 24 
>hours it grows almost to the full 2Gb. Right now it's at 1.8.
>Should I be concerned?

erm.. Read those numbers cloesly.. 1.125 gigs of cache...

Ideally your physical memory usage should always be 100% (ie: memfree = 0). 
That which isn't being used by programs should be used as disk cache until 
a process needs more ram in which case the disk cache shrinks.

Instead of looking at your memfree, take a look at memfree + buffers+ cached.

Also keep an eye on your swapfree. And it is ok for a small amount of swap 
to be used.. A good OS will realize that some pages in a processes memory 
haven't been accessed for days and will swap it out to make room for more 
disk cache. (It's quite typical for programs to have memory that's only 
used when they start up due to lazy programing).