Samba Drops Connections
David.Collier-Brown at canada.sun.com
Fri Sep 15 12:27:17 GMT 2000
I'm having problems with Samba dropping connections on the network.
We've recently installed a Cisco Catalyst switch, if that makes a
difference, but the log for one of the machines is as follows -
[2000/09/13 12:09:28, 1] smbd/service.c:close_cnum(557)
h77 (0.0.0.0) closed connection to service xx
[2000/09/13 12:09:35, 1] smbd/service.c:make_connection(521)
h77 (18.104.22.168) connect to service xx as user xx (uid=xxx, gid=xxx)
[2000/09/13 12:10:15, 0] smbd/oplock.c:oplock_break(922)
oplock_break: receive_smb timed out after 30 seconds.
oplock_break failed for file XXXXXX.XLS (dev = 806, inode =
[2000/09/13 12:10:15, 0] smbd/oplock.c:oplock_break(992)
oplock_break: client failure in break - shutting down this smbd.
[2000/09/13 12:10:15, 1] smbd/service.c:close_cnum(557)
[and oplocks are off]
I think the oplock break is a misleading message (although it
also may indicate a samba error).
The connection to the client is broken, and smbd is complaining
that it has to shut down: this may indicate an error in the
connection between samba and the client.
This is a copy of a message I sent to someone else about
Every so often these days (circa win98, win2k), we see error
like the following showing up in the logs:
[2000/09/08 18:06:24, 0]
write_socket_data: write failure. Error = Broken pipe
These are unexpected client disconnections, as seen by Samba.
If you happen to be using security = server, these can be
eliminated by setting keepalive = 0. If you are using any
other security setting, use keepalive = 30 to tell Samba to
clean up more often (this won't reduce the messages, though!)
They usually indicates an error by the client, which caused
1) blue screen
3) silently disconect and reconnect.
The latter is the annoying one...
The usual cause is a networking problem. What the team's seen
a lot lately are mismatches between ethernet cards and hubs...
Both ends of each connection between a hub and a machine must
be running at the same speed, either 10 or 100 Mbit/S and at the
same duplex setting (half- or full-duplex, sometimes called simplex
A mismatch is usually detectable using ftp: if copying in one
direction is an order of magnitude fast than the other, you have
a problem. Note that being a little slower one way than the other
is normal: my machine at work looks like this:
ftp> get gnuplot-3.7-sol8-sparc-local foo
200 PORT command successful.
150 ASCII data connection for gnuplot-3.7-sol8-sparc-local
226 ASCII Transfer complete.
local: foo remote: gnuplot-3.7-sol8-sparc-local
1163024 bytes received in 1.2 seconds (955.88 Kbytes/s)
ftp> put foo foo
200 PORT command successful.
150 ASCII data connection for foo (22.214.171.124,39394).
226 Transfer complete.
local: foo remote: foo
1163024 bytes sent in 0.45 seconds (2520.48 Kbytes/s)
So the "get" is 37% of the "put" speed (the put is writing to a
slower disk than the get was).
Looking at ethernet stats can help, too: netstat -i output
should look something like:
Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis
lo0 8232 loopback localhost 1904006 0 1904006 0 0
hme0 1500 elsbeth elsbeth 8278338 1 2280982 0 579602
The number of errors should be **very** low: I have about
1 in 12,100,000.
The number of collisions should be below 3% UNLESS you have
a cut-through (first generation) ethernet hub. I have 25.4%
because I have a cut-through hub on this machine.
The failing client can be found by using smbstatus repertedly.
Look at the "pid" column:
Samba version 2.0.7
Service uid gid pid machine
temp davecb staff 18310 elsbeth (126.96.36.199) Tue Sep
If elsbeth had been failing and reconnecting, a previous
smbstatus would have looked the same, but the pid would be
different, as Samba starts a new process on each (re-)connection.
David Collier-Brown, | Always do right. This will gratify some people
185 Ellerslie Ave., | and astonish the rest. -- Mark Twain
Willowdale, Ontario | //www.oreilly.com/catalog/samba/author.html
Work: (905) 415-2849 Home: (416) 223-8968 Email: davecb at canada.sun.com
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