samba - Jan 2010 - max smbd processes

Samba 3.2.5 on Debian Lenny

From: http://www.samba.org/samba/docs/server_security.html
"Samba is able to limit the number of concurrent connections when smbd is
launched as a daemon (not from inetd). The 'max smbd processes' smb.conf
option
allows Administrators to define the maximum number of smbd processes running at
any given point in time. Any further attempts from clients to connect to the
server will be rejected."

I'm using max smbd processes for another reason.  I'm trying to optimize
memory
usage on this box, which really only ever has one samba client machine
connecting.  I'm trying to get the number of smbd processes down to 1 but to
this point have failed.  I have in /etc/samba/smb.conf:

max smbd processes = 1

Yet once restarting samba and connecting to a share, I get this:

[04:41:16][root at greer]/$ ps -ef|grep smbd
root      8586     1  0 00:12 ?        00:00:00 /usr/sbin/smbd -D
root      8591  8586  0 00:12 ?        00:00:00 /usr/sbin/smbd -D
stan      8596  8586  0 00:13 ?        00:00:56 /usr/sbin/smbd -D

top:
 8586 root      20   0 12368 2828 2168 S    0  0.7   0:00.12 smbd
 8591 root      20   0 12368  984  340 S    0  0.3   0:00.00 smbd
 8596 stan      20   0 12912 3972 2896 S    0  1.0   0:56.46 smbd

I've set max smbd processes to 1, yet I see 3 smbd processes.  Is something
broken?  Is "max smbd processes" not an accurate description?  Would
it better
be described as "max smbd concurrent clients" or "max smbd user
processes"?

I can understand the need for a master daemon process that spawns children for
each connection, but at most that should require 2 smbd processes, not 3.  As
you can see from the top output, only one smbd process is actually servicing a
client.  One is completely idle, sucking up resources.  The other appears to be
the master which spawns the children.

I know I'm in a fringe scenario here, as most people aren't going to try
to
limit smbd processes to 1.  I'm just wondering why the documentation is so
exactly specific as to the nature of this config option, but why the option
doesn't work the way it is described.  Is this a "truth in
advertising" issue,
or am I missing something else in my config to make this config directive work
as advertised?

Thanks.

-- 
Stan

On Wed, Jan 27, 2010 at 05:03:37PM -0600, Stan Hoeppner
wrote:
> Samba 3.2.5 on Debian Lenny
> 
> From: http://www.samba.org/samba/docs/server_security.html
> "Samba is able to limit the number of concurrent connections when smbd
is
> launched as a daemon (not from inetd). The 'max smbd processes'
smb.conf option
> allows Administrators to define the maximum number of smbd processes
running at
> any given point in time. Any further attempts from clients to connect to
the
> server will be rejected."
> 
> I'm using max smbd processes for another reason.  I'm trying to
optimize memory
> usage on this box, which really only ever has one samba client machine
> connecting.  I'm trying to get the number of smbd processes down to 1
but to
> this point have failed.  I have in /etc/samba/smb.conf:
> 
> max smbd processes = 1
> 
> Yet once restarting samba and connecting to a share, I get this:
> 
> [04:41:16][root at greer]/$ ps -ef|grep smbd
> root      8586     1  0 00:12 ?        00:00:00 /usr/sbin/smbd -D
> root      8591  8586  0 00:12 ?        00:00:00 /usr/sbin/smbd -D
> stan      8596  8586  0 00:13 ?        00:00:56 /usr/sbin/smbd -D
> 
> top:
>  8586 root      20   0 12368 2828 2168 S    0  0.7   0:00.12 smbd
>  8591 root      20   0 12368  984  340 S    0  0.3   0:00.00 smbd
>  8596 stan      20   0 12912 3972 2896 S    0  1.0   0:56.46 smbd
> 
> I've set max smbd processes to 1, yet I see 3 smbd processes.  Is
something
> broken?
No.
> Is "max smbd processes" not an accurate description?  Would it
better
> be described as "max smbd concurrent clients" or "max smbd
user processes"?
Yes, that's a better description.
> I can understand the need for a master daemon process that spawns children
for
> each connection, but at most that should require 2 smbd processes, not 3. 
As
> you can see from the top output, only one smbd process is actually
servicing a
> client.  One is completely idle, sucking up resources.  The other appears
to be
> the master which spawns the children.
There's also the printer background lpq updater process, that's the
third one. We should probably update the description to make this
clear. It's all working as designed. You can always comment out
the code for this (it's in printing/printing.c:start_background_queue())
if you are resource constrained.

Jeremy.