Memory problems in Sendmail?

[benjithegreat98]

I am using sendmail as a means to block spam. We have an old 400 MHz PC with 384 Mb of RAM. We use this computer to accept the mail into our organization and relay it to our Domino server. We do this because the Domino server is too old to use DNS Blacklists and we don't have the money to upgrade it for that. The problem is that when I boot up slack, free -omt will report 85 M used and 291M free. The next day or 16 hrs later it will read 275M used 101M free. and it will continue to shrink. When I do "ps aux" or "top" it doesn't report anything using that much memory. I also had this problem with Redhat 9 and sendmail 8.12.8. I thought it was spamassassin doing it but I was wrong because I turned it off and it still persisted. So I moved to Slack and it is still doing it.

 

[vip386]

Hi Benji,

The memory you think you are losing is probably being used by the disk cache, which is where the Linux kernel is caching disk files in RAM to save disk accesses and keeping buffers in memory. That cache memory is easily usable by applications.

Try doing a
$ free -m

Oh a RedHat system I use with 256MB of RAM, it looks like this:

total used free shared buffers cached
Mem: 251 247 3 68 23 128
-/+ buffers/cache: 95 156
Swap: 384 0 384

Look at the 2nd line "-/+ buffers/cache". What it shows is that the real used memory is 95 MB and the free memory is 156 MB -- because the memory used by the disk cache is almost instantly freeable to be used by programs.

Hope this helped. -David