[Samba] Accumulating smbd processes and sockets in CLOSE_WAIT state

Christoph Kaegi kaph at zhaw.ch
Thu Oct 25 19:48:04 GMT 2007

Hello list

Our central fileserver is a Samba 3.0.25b on Solaris 9 and has 
10'000 users (several hundreds at the same time).

This week it died on us and when I inspected the machine, it
was out of 8GB Memory and 16GB Swap because thousands of 
smbd processes were running.
netstat -na showed that many hundreds of connections to 
port 445 were in CLOSE_WAIT state.

We first thought it could be some sort of DoS Attack, but now I 
also discovered a lot of the following entries in smbd.log at 
the times the server became unresponsive:

---------------------------- 8< ----------------------------
[2007/10/25 15:40:30, 0] lib/util_tdb.c:tdb_chainlock_with_timeout_internal(84)
  tdb_chainlock_with_timeout_internal: alarm (10) timed out for key replay cache mutex in tdb /etc/samba/private/secrets.tdb
---------------------------- 8< ----------------------------

The same thing happened three times now, all of them at a time
when presumably a peak of users (around 600-900) tried to use
the server. Every time the number of network connections in
CLOSE_WAIT state and the number of smbd processes was massively 

Others seem to have similar problems (like 

The fileserver has been performing OK now for several months 
with this Samba Release.

I'd be grateful if anybody could give me some insight
about how we can solve this.
Loosing fileservice for all of staff and students 
several times a week builds some considerable pressure
on me...


Christoph Kaegi                                           kaph at zhaw.ch

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