Chapter 11. Additional Samba Information

time server

Samba always operates as an SMB time server, matching the behavior of Windows systems. However, Samba's default is not to advertise itself as a time server to the network. When this option is set to yes, Samba advertises itself as an SMB time server:

[global]
    time service = yes

time offset

To deal with clients that don't properly process daylight savings time, Samba provides the time offset option. If set, it adds the specified number of minutes to the current time. This is handy if you're in Newfoundland and Windows doesn't know about the 30-minute time difference there:

[global]
    time offset = 30

dos filetimes

Traditionally, only the root user and the owner of a file can change its last-modified date on a Unix system. The share-level dos filetimes option allows the Samba server to mimic the characteristics of a DOS or Windows system: any user can change the last-modified date on a file in that share if she has write permission to it. To do this, Samba uses its root privileges to modify the timestamp on the file.

By default, this option is disabled. Setting this option to yes is often necessary to allow PC make programs to work properly. Without it, they cannot change the last-modified date themselves. This often results in the program thinking all files need recompiling when they really don't.

dos filetime resolution

[data]
    dos filetime resolution = yes

We recommend using this option only if you are using Microsoft Visual C++ on a Samba share that supports opportunistic locking.

fake directory create times

[data]
    fake directory create times = yes

magic script

[accounting]
    magic script = tally.sh

Samba continually monitors the files in that share. If one by the name of tally.sh is closed (after being opened) by a user, Samba will execute the contents of that file locally. The file will be passed to the shell to execute; it must therefore be a legal Unix shell script. This means that it must have newline characters as line endings instead of Windows CRLFs. In addition, you need to use the #! directive at the beginning of the file to indicate under which shell or interpreter the script should run, unless the script is for the default shell on your system.

magic output

This option specifies an output file to which the script specified by the magic script option will send output. You must specify a filename in a writable directory:

[accounting]
    magic script = tally.sh
    magic output = /var/log/magicoutput

If this option is omitted, the default output file is the name of the script (as stated in the magic script option) with the extension .out appended onto it.

client code page

Table 11-4. Valid code pages with Samba 2.0

You can set the client code page as follows:

[global]
    client code page = 852

The default value of this option is 850, for MS-DOS Latin 1. You can use the make_smbcodepage tool that comes with Samba (by default in /usr/local/samba/bin ) to create your own SMB code pages, in the event that those listed earlier are not sufficient.

character set

Table 11-5. Valid character sets

Normally, the character set option is disabled completely.

coding system

Table 11-6. Valid coding-system parameters

valid chars

valid chars = Î
valid chars = 0450:0420 0x0A20:0x0A00
valid chars = A:a

Each character in the list specified should be separated by spaces. If there is a colon between two characters or a numerical equivalent, the data to the left of the colon is considered an uppercase character, while the data to the right is considered the lowercase character. You can represent characters both by literals (if you can type them) and by octal, hexadecimal, or decimal Unicode equivalents.

message command

[global]
    message command = /bin/mail -s "SMB Message From %f on %m" root <%s; rm %s

Note the use of variables here. The %s variable will be replaced by the name of the file in which the message resides. This file should be deleted when the command is finished with it; otherwise, a buildup of message files will collect on the Samba server. In addition, the command must either exit quickly or fork its own process (using an & after the command); otherwise, the client might suspend and wait for notification that the command was sent successfully before continuing.

Table 11-8. message command variables

dfree command

This global option is used on systems that incorrectly determine the free space left on the disk. So far, the only confirmed system that needs this option set is Ultrix. There is no default value for this option, which means that Samba already knows how to compute the free disk space on its own and the results are considered reliable. You can override it as follows:

[global]
    dfree command = /usr/local/bin/dfree

This option should point to a script that returns the total disk space in a block and the number of available blocks. The Samba documentation recommends the following as a usable script:

#!/bin/sh
df $1 | tail -1 | awk '{print $2" "$4}'

On System V machines, the following will work:

#!/bin/sh
/usr/bin/df $1 | tail -1 | awk '{print $3" "$5}'

fstype

Table 11-10. Filesystem types

The default value for this option is NTFS, which represents a Windows NT filesystem. There probably isn't a need to specify any other type of filesystem. However, if you need to, you can override the default value per share as follows:

[data]
    fstype = FAT

keepalive

This global option specifies the number of seconds that Samba waits between sending NetBIOS keepalive packets. These packets are used to ping a client to detect whether it is still alive and on the network. The default value for this option is 300 (5 minutes), which you can override as follows:

[global]
    keepalive = 600

The value of 600 (10 minutes) is good for networks populated by reliable clients. If your network contains relatively unreliable clients, you might prefer to set keepalive to a lower value, such as 30. If keepalive is set to 0, no NetBIOS keepalive packets will be sent. See also the deadtime parameter.

max disk size

This global option specifies an illusory limit, in megabytes, for each share that Samba is offering. It only affects how much disk space Samba reports the share as having and does not prevent more disk space from actually being available for use. You would typically set this option to prevent clients with older operating systems—or running buggy applications—from being confused by large disk spaces. For example, some older Windows applications become confused when they encounter a share larger than 1 gigabyte. To work around this problem, max disk size can be set as follows:

[global]
    max disk size = 1000

The default value for this option is 0, which means there is no upper limit.

max mux

This global option specifies the maximum number of concurrent SMB operations Samba allows. The default value for this option is 50. You can override it as follows:

[global]
    max mux = 100

max open files

This global option specifies the maximum number of open files that Samba should allow at any given time for all processes. This value must be equal to or less than the amount allowed by the operating system, which varies from system to system. The default value for this option is 10000. You can override it as follows:

[global]
    max open files = 8000

max xmit

This global option sets the maximum size of packets that Samba exchanges with a client. In rare cases, setting a smaller maximum packet size can increase performance, especially with Windows for Workgroups. In Samba versions up to 2.2.5, the default value for this option is 65535. In 2.2.7 and later versions, the default was changed to 16644 to match the behavior of Windows 2000 and improve support for Windows NT 4.0. You can override the default as follows:

[global]
    max xmit = 4096

nt pipe support

[global]
    nt pipe support = yes

nt smb support

This global option is used by developers to negotiate NT-specific SMB options with Windows NT/2000/XP clients. The Samba Team has discovered that slightly better performance comes from setting this value to no. However, as a user, you should probably not override the default:

[global]
    nt smb support = yes

ole locking compatibility

This global option turns off Samba's internal byte-range locking manipulation in files, which gives compatibility with Object Linking and Embedding (OLE) applications that use high byte-range locks as a method of interprocess communication. The default value for this option is yes. If you trust your Unix locking mechanisms, you can override it as follows:

[global]
    ole locking compatibility = no

panic action

This global option specifies a command to execute in the event that Samba encounters a fatal error when loading or running. There is no default value for this option. You can specify an action as follows:

[global]
    panic action = /bin/csh -c
          'xedit <<: "Samba has shutdown unexpectedly";:'

set directory

[data]
    set directory = yes

status

This global option indicates whether Samba should log all active connections to a status file. This file is used only by the smbstatus command. If you have no intentions of using this command, you can set this option to no, which can result in a small increase of speed on the server. The default value for this option is yes. You can override it as follows:

[global]
    status = no

strict sync

This share-level option determines whether Samba honors all requests to perform a disk sync when requested to do so by a client. Many Windows clients request a disk sync when they are really just trying to flush data to their own open files. In this case, a disk sync is generally unnecessary on Unix due to its high reliability, and it mostly has the effect of substantially reducing the performance of the Samba host system. The default value for this option is no, which allows the superfluous disk sync requests to be ignored. You can override the default as follows:

[data]
    strict sync = yes

sync always

This share-level option decides whether every write to disk should be followed by a disk synchronization before the write call returns control to the client. Even if the value of this option is no, clients can request a disk synchronization; see the earlier strict sync option. The default value for this option is no. You can override it per share as follows:

[data]
    sync always = yes

strip dot

This global option determines whether to remove the trailing dot from Unix filenames that are formatted with a dot at the end. The default value for this option is no. You can override it per share as follows:

[global]
    strip dot = yes

change notify timeout

Samba performs this function for its clients at an interval that defaults to 1 minute (60 seconds). Performing these checks too often can slow down the server considerably; however, you can use this option to specify an alternate time that Samba should wait between performing checks:

[global]
    change notify timeout = 30

stat cache

stat cache size