I'm only running on a low memory system so would like to run only one clamd, but i have googled for hours trying to find the answer with no luck. I tried clamscan instead but it takes far too long to scan each email.

Does anyone know how to limit the clamd to run only one 'thread'?


  • Just a guess, but have you tried the MaxThreads setting in clamd.conf?
    – depquid
    Mar 16, 2013 at 15:09
  • yes, and still starts 2 processes even with MaxThreads 1
    – Christian
    Mar 16, 2013 at 15:53
  • Two processes or two threads?
    – depquid
    Mar 16, 2013 at 16:19
  • As you see it in the image. I thought it was two threads but they have a different PID, but if you shut one down, the other goes, which to me is more like threads?
    – Christian
    Mar 16, 2013 at 16:45
  • 1
    Centos 6.3 x86_64 512MB RAM. Its one of amazon's EC2 micro servers
    – Christian
    Mar 16, 2013 at 16:53

1 Answer 1


Your screenshot shows the threads have not used any time at all, so this shouldn't be a concern (several clamd running will at least share the executable, and probably most of the data areas too, so they should not be a memory burden). And it might be that there is a principal clamd process, which spawns the worker threads and manages them. So two clamds running would be the right number for one thread.

What are you using that machine for? Is that the mail server? Serving mail by POP or IMAP (or via webmail) needs memory. RAM is cheap, buy some more...

  • It's running on one of Amazon's EC2 micro instances which is a free solution we offer to start-up businesses in my country. So we cant upgrade the RAM unfortunately :( I'm contemplating having a dedicated EC2 running spam/AV checking though for all clients.
    – Christian
    Mar 17, 2013 at 8:37

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