Occasionally, we need to find out what Samba is up to. This is especially true when Samba is performing an unexpected action or is not performing at all. To find out this information, we need to check Samba's log files to see exactly why it did what it did.
Samba log files can be as brief or verbose as you like. Here is an example of what a Samba log file looks like:
[1999/07/21 13:23:25, 3] smbd/service.c:close_cnum(514)
phoenix (192.168.220.101) closed connection to service IPC$
[1999/07/21 13:23:25, 3] smbd/connection.c:yield_connection(40)
Yielding connection to IPC$
[1999/07/21 13:23:25, 3] smbd/process.c:process_smb(615)
Transaction 923 of length 49
[1999/07/21 13:23:25, 3] smbd/process.c:switch_message(448)
switch message SMBread (pid 467)
[1999/07/21 13:23:25, 3] lib/doscalls.c:dos_ChDir(336)
dos_ChDir to /home/samba
[1999/07/21 13:23:25, 3] smbd/reply.c:reply_read(2199)
read fnum=4207 num=2820 nread=2820
[1999/07/21 13:23:25, 3] smbd/process.c:process_smb(615)
Transaction 924 of length 55
[1999/07/21 13:23:25, 3] smbd/process.c:switch_message(448)
switch message SMBreadbraw (pid 467)
[1999/07/21 13:23:25, 3] smbd/reply.c:reply_readbraw(2053)
readbraw fnum=4207 start=130820 max=1276 min=0 nread=1276
[1999/07/21 13:23:25, 3] smbd/process.c:process_smb(615)
Transaction 925 of length 55
[1999/07/21 13:23:25, 3] smbd/process.c:switch_message(448)
switch message SMBreadbraw (pid 467)
Many of these options are of use only to Samba programmers. However, we will go over the meaning of some of these entries in more detail in Chapter 9,
Troubleshooting Samba.
Samba contains six options that allow users to describe how and where logging information should be written. Each of these options are global options and cannot appear inside a share definition. Here is an up-to-date configuration file that covers each of the share and logging options that we've seen so far:
[global]
netbios name = HYDRA
server string = Samba %v on (%I)
workgroup = SIMPLE
# Networking configuration options
hosts allow = 192.168.220. 134.213.233. localhost
hosts deny = 192.168.220.102
interfaces = 192.168.220.100/255.255.255.0 \
134.213.233.110/255.255.255.0
bind interfaces only = yes
# Debug logging information
log level = 2
log file = /var/log/samba.log.%m
max log size = 50
debug timestamp = yes
[data]
path = /home/samba/data
browseable = yes
guest ok = yes
comment = Data Drive
volume = Sample-Data-Drive
writeable = yes
Here, we've added a custom log file that reports information up to debug level 2. This is a relatively light debugging level. The logging level ranges from 1 to 10, where level 1 provides only a small amount of information and level 10 provides a plethora of low-level information. Level 2 will provide us with useful debugging information without wasting disk space on our server. In practice, you should avoid using log levels greater than 3 unless you are programming Samba.
This file is located in the
/var/log directory thanks to the
log
file configuration option. However, we can use variable substitution to create log files specifically for individual users or clients, such as with the
%m variable in the following line:
log file = /usr/local/logs/samba.log.%m
Isolating the log messages can be invaluable in tracking down a network error if you know the problem is coming from a specific machine or user.
We've added another precaution to the log files: no one log file can exceed 50 kilobytes in size, as specified by the
max
log
size option. If a log file exceeds this size, the contents are moved to a file with the same name but with the suffix
.old appended. If the
.old file already exists, it is overwritten and its contents are lost. The original file is cleared, waiting to receive new logging information. This prevents the hard drive from being overwhelmed with Samba log files during the life of our daemons.
For convenience, we have decided to leave the debug timestamp in the logs with the
debug
timestamp option, which is the default behavior. This will place a timestamp next to each message in the logging file. If we were not interested in this information, we could specify
no for this option instead.
