Documentation Links/samba4-smb.conf

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SMB.CONF(5) File Formats and Conventions SMB.CONF(5)


NAME
smb.conf - The configuration file for the Samba suite

SYNOPSIS
The smb.conf file is a configuration file for the Samba suite. smb.conf contains runtimeconfiguration information for the Samba programs. The smb.conf file is designed to be configured andadministered by the swat(8) program. The complete description of the file format and possibleparameters held within are here for reference purposes.

FILE FORMAT
The file consists of sections and parameters. A section begins with the name of the section insquare brackets and continues until the next section begins. Sections contain parameters of theform:

name = value

The file is line-based - that is, each newline-terminated line represents either a comment, asection name or a parameter.

Section and parameter names are not case sensitive.

Only the first equals sign in a parameter is significant. Whitespace before or after the firstequals sign is discarded. Leading, trailing and internal whitespace in section and parameter namesis irrelevant. Leading and trailing whitespace in a parameter value is discarded. Internalwhitespace within a parameter value is retained verbatim.

Any line beginning with a semicolon (“;”) or a hash (“#”) character is ignored, as are linescontaining only whitespace.

Any line ending in a “\” is continued on the next line in the customary UNIX fashion.

The values following the equals sign in parameters are all either a string (no quotes needed) or aboolean, which may be given as yes/no, 1/0 or true/false. Case is not significant in boolean values,but is preserved in string values. Some items such as create masks are numeric.

SECTION DESCRIPTIONS
Each section in the configuration file (except for the [global] section) describes a shared resource(known as a “share”). The section name is the name of the shared resource and the parameters withinthe section define the shares attributes.

There are three special sections, [global], [homes] and [printers], which are described underspecial sections. The following notes apply to ordinary section descriptions.

A share consists of a directory to which access is being given plus a description of the accessrights which are granted to the user of the service. Some housekeeping options are also specifiable.

Sections are either file share services (used by the client as an extension of their native filesystems) or printable services (used by the client to access print services on the host running theserver).

Sections may be designated guest services, in which case no password is required to access them. Aspecified UNIX guest account is used to define access privileges in this case.

Sections other than guest services will require a password to access them. The client provides theusername. As older clients only provide passwords and not usernames, you may specify a list ofusernames to check against the password using the user = option in the share definition. For modernclients such as Windows 95/98/ME/NT/2000, this should not be necessary.

The access rights granted by the server are masked by the access rights granted to the specified orguest UNIX user by the host system. The server does not grant more access than the host systemgrants.

The following sample section defines a file space share. The user has write access to the path/home/bar. The share is accessed via the share name foo:

[foo] path = /home/bar read only = no

The following sample section defines a printable share. The share is read-only, but printable. Thatis, the only write access permitted is via calls to open, write to and close a spool file. The guestok parameter means access will be permitted as the default guest user (specified elsewhere):

[aprinter] path = /usr/spool/public read only = yes printable = yes guest ok = yes

SPECIAL SECTIONS
The [global] sectionParameters in this section apply to the server as a whole, or are defaults for sections that do notspecifically define certain items. See the notes under PARAMETERS for more information.

  The [homes] sectionIf a section called [homes] is included in the configuration file, services connecting clients totheir home directories can be created on the fly by the server.

When the connection request is made, the existing sections are scanned. If a match is found, it isused. If no match is found, the requested section name is treated as a username and looked up in thelocal password file. If the name exists and the correct password has been given, a share is createdby cloning the [homes] section.

Some modifications are then made to the newly created share:

· The share name is changed from homes to the located username.

· If no path was given, the path is set to the user´s home directory.

If you decide to use a path = line in your [homes] section, it may be useful to use the %S macro.For example:

path = /data/pchome/%S

is useful if you have different home directories for your PCs than for UNIX access.

This is a fast and simple way to give a large number of clients access to their home directorieswith a minimum of fuss.

A similar process occurs if the requested section name is “homes”, except that the share name is notchanged to that of the requesting user. This method of using the [homes] section works well ifdifferent users share a client PC.

The [homes] section can specify all the parameters a normal service section can specify, though somemake more sense than others. The following is a typical and suitable [homes] section:

[homes] read only = no

An important point is that if guest access is specified in the [homes] section, all home directorieswill be visible to all clients without a password. In the very unlikely event that this is actuallydesirable, it is wise to also specify read only access.

The browseable flag for auto home directories will be inherited from the global browseable flag, notthe [homes] browseable flag. This is useful as it means setting browseable = no in the [homes]section will hide the [homes] share but make any auto home directories visible.

  The [printers] sectionThis section works like [homes], but for printers.

If a [printers] section occurs in the configuration file, users are able to connect to any printerspecified in the local host´s printcap file.

When a connection request is made, the existing sections are scanned. If a match is found, it isused. If no match is found, but a [homes] section exists, it is used as described above. Otherwise,the requested section name is treated as a printer name and the appropriate printcap file is scannedto see if the requested section name is a valid printer share name. If a match is found, a newprinter share is created by cloning the [printers] section.

A few modifications are then made to the newly created share:

· The share name is set to the located printer name

· If no printer name was given, the printer name is set to the located printer name

· If the share does not permit guest access and no username was given, the username is set to the located printer name.

The [printers] service MUST be printable - if you specify otherwise, the server will refuse to loadthe configuration file.

Typically the path specified is that of a world-writeable spool directory with the sticky bit set onit. A typical [printers] entry looks like this:

[printers] path = /usr/spool/public guest ok = yes printable = yes

All aliases given for a printer in the printcap file are legitimate printer names as far as theserver is concerned. If your printing subsystem doesn´t work like that, you will have to set up apseudo-printcap. This is a file consisting of one or more lines like this:

alias|alias|alias|alias...

Each alias should be an acceptable printer name for your printing subsystem. In the [global]section, specify the new file as your printcap. The server will only recognize names found in yourpseudo-printcap, which of course can contain whatever aliases you like. The same technique could beused simply to limit access to a subset of your local printers.

An alias, by the way, is defined as any component of the first entry of a printcap record. Recordsare separated by newlines, components (if there are more than one) are separated by vertical barsymbols (|).

Note On SYSV systems which use lpstat to determine what printers are defined on the system you may be able to use printcap name = lpstat to automatically obtain a list of printers. See the printcap name option for more details.

USERSHARES
Starting with Samba version 3.0.23 the capability for non-root users to add, modify, and deletetheir own share definitions has been added. This capability is called usershares and is controlledby a set of parameters in the [global] section of the smb.conf. The relevant parameters are :

usershare allow guests Controls if usershares can permit guest access.

usershare max shares Maximum number of user defined shares allowed.

usershare owner only If set only directories owned by the sharing user can be shared.

usershare path Points to the directory containing the user defined share definitions. The filesystem permissions on this directory control who can create user defined shares.

usershare prefix allow list Comma-separated list of absolute pathnames restricting what directories can be shared. Only directories below the pathnames in this list are permitted.

usershare prefix deny list Comma-separated list of absolute pathnames restricting what directories can be shared. Directories below the pathnames in this list are prohibited.

usershare template share Names a pre-existing share used as a template for creating new usershares. All other share parameters not specified in the user defined share definition are copied from this named share.

To allow members of the UNIX group foo to create user defined shares, create the directory tocontain the share definitions as follows:

Become root:

mkdir /usr/local/samba/lib/usershares chgrp foo /usr/local/samba/lib/usershares chmod 1770 /usr/local/samba/lib/usershares

Then add the parameters

usershare path = /usr/local/samba/lib/usershares usershare max shares = 10 # (or the desired number of shares)

to the global section of your smb.conf. Members of the group foo may then manipulate the userdefined shares using the following commands.

net usershare add sharename path [comment] [acl] [guest_ok=[y|n]] To create or modify (overwrite) a user defined share.

net usershare delete sharename To delete a user defined share.

net usershare list wildcard-sharename To list user defined shares.

net usershare info wildcard-sharename To print information about user defined shares.

PARAMETERS
Parameters define the specific attributes of sections.

Some parameters are specific to the [global] section (e.g., security). Some parameters are usable inall sections (e.g., create mask). All others are permissible only in normal sections. For thepurposes of the following descriptions the [homes] and [printers] sections will be considerednormal. The letter G in parentheses indicates that a parameter is specific to the [global] section.The letter S indicates that a parameter can be specified in a service specific section. All Sparameters can also be specified in the [global] section - in which case they will define thedefault behavior for all services.

Parameters are arranged here in alphabetical order - this may not create best bedfellows, but atleast you can find them! Where there are synonyms, the preferred synonym is described, others referto the preferred synonym.

VARIABLE SUBSTITUTIONS
Many of the strings that are settable in the config file can take substitutions. For example theoption “path = /tmp/%u” is interpreted as “path = /tmp/john” if the user connected with the usernamejohn.

These substitutions are mostly noted in the descriptions below, but there are some generalsubstitutions which apply whenever they might be relevant. These are:

%U session username (the username that the client wanted, not necessarily the same as the one they got).

%G primary group name of %U.

%h the Internet hostname that Samba is running on.

%m the NetBIOS name of the client machine (very useful).

This parameter is not available when Samba listens on port 445, as clients no longer send this information. If you use this macro in an include statement on a domain that has a Samba domain controller be sure to set in the [global] section smb ports = 139. This will cause Samba to not listen on port 445 and will permit include functionality to function as it did with Samba 2.x.

%L the NetBIOS name of the server. This allows you to change your config based on what the client calls you. Your server can have a “dual personality”.

%M the Internet name of the client machine.

%R the selected protocol level after protocol negotiation. It can be one of CORE, COREPLUS, LANMAN1, LANMAN2, NT1, SMB2_02, SMB2_10, SMB2_22, SMB2_24, SMB3_00 or SMB2_FF.

%d the process id of the current server process.

%a The architecture of the remote machine. It currently recognizes Samba (Samba), the Linux CIFS file system (CIFSFS), OS/2, (OS2), Mac OS X (OSX), Windows for Workgroups (WfWg), Windows 9x/ME (Win95), Windows NT (WinNT), Windows 2000 (Win2K), Windows XP (WinXP), Windows XP 64-bit(WinXP64), Windows 2003 including 2003R2 (Win2K3), and Windows Vista (Vista). Anything else will be known as UNKNOWN.

%I the IP address of the client machine.

Before 4.0.0 it could contain IPv4 mapped IPv6 addresses, now it only contains IPv4 or IPv6 addresses.

%i the local IP address to which a client connected.

Before 4.0.0 it could contain IPv4 mapped IPv6 addresses, now it only contains IPv4 or IPv6 addresses.

%T the current date and time.

%D name of the domain or workgroup of the current user.

%w the winbind separator.

%$(envvar) the value of the environment variable envar.

The following substitutes apply only to some configuration options (only those that are used when aconnection has been established):

%S the name of the current service, if any.

%P the root directory of the current service, if any.

%u username of the current service, if any.

%g primary group name of %u.

%H the home directory of the user given by %u.

%N the name of your NIS home directory server. This is obtained from your NIS auto.map entry. If you have not compiled Samba with the --with-automount option, this value will be the same as %L.

%p the path of the service´s home directory, obtained from your NIS auto.map entry. The NIS auto.map entry is split up as %N:%p.

There are some quite creative things that can be done with these substitutions and other smb.confoptions.

NAME MANGLING
Samba supports name mangling so that DOS and Windows clients can use files that don´t conform to the8.3 format. It can also be set to adjust the case of 8.3 format filenames.

There are several options that control the way mangling is performed, and they are grouped hererather than listed separately. For the defaults look at the output of the testparm program.

These options can be set separately for each service.

The options are:

case sensitive = yes/no/auto controls whether filenames are case sensitive. If they aren´t, Samba must do a filename search and match on passed names. The default setting of auto allows clients that support case sensitive filenames (Linux CIFSVFS and smbclient 3.0.5 and above currently) to tell the Samba server on a per-packet basis that they wish to access the file system in a case-sensitive manner (to support UNIX case sensitive semantics). No Windows or DOS system supports case-sensitive filename so setting this option to auto is that same as setting it to no for them. Default auto.

default case = upper/lower controls what the default case is for new filenames (ie. files that don´t currently exist in the filesystem). Default lower. IMPORTANT NOTE: As part of the optimizations for directories containing large numbers of files, the following special case applies. If the options case sensitive = yes, preserve case = No, and short preserve case = No are set, then the case of all incoming client filenames, not just new filenames, will be modified. See additional notes below.

preserve case = yes/no controls whether new files (ie. files that don´t currently exist in the filesystem) are created with the case that the client passes, or if they are forced to be the default case. Default yes.

short preserve case = yes/no controls if new files (ie. files that don´t currently exist in the filesystem) which conform to 8.3 syntax, that is all in upper case and of suitable length, are created upper case, or if they are forced to be the default case. This option can be used with preserve case = yes to permit long filenames to retain their case, while short names are lowercased. Default yes.

By default, Samba 3.0 has the same semantics as a Windows NT server, in that it is case insensitivebut case preserving. As a special case for directories with large numbers of files, if the caseoptions are set as follows, "case sensitive = yes", "case preserve = no", "short preserve case = no"then the "default case" option will be applied and will modify all filenames sent from the clientwhen accessing this share.

REGISTRY-BASED CONFIGURATION
Starting with Samba version 3.2.0, the capability to store Samba configuration in the registry isavailable. The configuration is stored in the registry key HKLM\Software\Samba\smbconf. There aretwo levels of registry configuration:

1. Share definitions stored in registry are used. This is triggered by setting the global parameter registry shares to “yes” in smb.conf.

The registry shares are loaded not at startup but on demand at runtime by smbd. Shares defined in smb.conf take priority over shares of the same name defined in registry.

2. Global smb.conf options stored in registry are used. This can be activated in two different ways:

Firstly, a registry only configuration is triggered by setting config backend = registry in the [global] section of smb.conf. This resets everything that has been read from config files to this point and reads the content of the global configuration section from the registry. This is the recommended method of using registry based configuration.

Secondly, a mixed configuration can be activated by a special new meaning of the parameter include = registry in the [global] section of smb.conf. This reads the global options from registry with the same priorities as for an include of a text file. This may be especially useful in cases where an initial configuration is needed to access the registry.

Activation of global registry options automatically activates registry shares. So in the registry only case, shares are loaded on demand only.

Note: To make registry-based configurations foolproof at least to a certain extent, the use of lockdirectory and config backend inside the registry configuration has been disabled: Especially bychanging the lock directory inside the registry configuration, one would create a broken setup wherethe daemons do not see the configuration they loaded once it is active.

The registry configuration can be accessed with tools like regedit or net (rpc) registry in the keyHKLM\Software\Samba\smbconf. More conveniently, the conf subcommand of the net(8) utility offers adedicated interface to read and write the registry based configuration locally, i.e. directlyaccessing the database file, circumventing the server.

EXPLANATION OF EACH PARAMETER
abort shutdown script (G)

This a full path name to a script called by smbd(8) that should stop a shutdown procedure issued by the shutdown script.

If the connected user possesses the SeRemoteShutdownPrivilege, right, this command will be run as root.

Default: abort shutdown script = ""

Example: abort shutdown script = /sbin/shutdown -c

access based share enum (S)

If this parameter is yes for a service, then the share hosted by the service will only be visible to users who have read or write access to the share during share enumeration (for example net view \\sambaserver). This has parallels to access based enumeration, the main difference being that only share permissions are evaluated, and security descriptors on files contained on the share are not used in computing enumeration access rights.

Default: access based share enum = no

acl check permissions (S)

Please note this parameter is now deprecated in Samba 3.6.2 and will be removed in a future version of Samba.

This boolean parameter controls what smbd(8)does on receiving a protocol request of "open for delete" from a Windows client. If a Windows client doesn´t have permissions to delete a file then they expect this to be denied at open time. POSIX systems normally only detect restrictions on delete by actually attempting to delete the file or directory. As Windows clients can (and do) "back out" a delete request by unsetting the "delete on close" bit Samba cannot delete the file immediately on "open for delete" request as we cannot restore such a deleted file. With this parameter set to true (the default) then smbd checks the file system permissions directly on "open for delete" and denies the request without actually deleting the file if the file system permissions would seem to deny it. This is not perfect, as it´s possible a user could have deleted a file without Samba being able to check the permissions correctly, but it is close enough to Windows semantics for mostly correct behaviour. Samba will correctly check POSIX ACL semantics in this case.

If this parameter is set to "false" Samba doesn´t check permissions on "open for delete" and allows the open. If the user doesn´t have permission to delete the file this will only be discovered at close time, which is too late for the Windows user tools to display an error message to the user. The symptom of this is files that appear to have been deleted "magically" re-appearing on a Windows explorer refresh. This is an extremely advanced protocol option which should not need to be changed. This parameter was introduced in its final form in 3.0.21, an earlier version with slightly different semantics was introduced in 3.0.20. That older version is not documented here.

Default: acl check permissions = True

acl group control (S)

In a POSIX filesystem, only the owner of a file or directory and the superuser can modify the permissions and ACLs on a file. If this parameter is set, then Samba overrides this restriction, and also allows the primary group owner of a file or directory to modify the permissions and ACLs on that file.

On a Windows server, groups may be the owner of a file or directory - thus allowing anyone in that group to modify the permissions on it. This allows the delegation of security controls on a point in the filesystem to the group owner of a directory and anything below it also owned by that group. This means there are multiple people with permissions to modify ACLs on a file or directory, easing manageability.

This parameter allows Samba to also permit delegation of the control over a point in the exported directory hierarchy in much the same way as Windows. This allows all members of a UNIX group to control the permissions on a file or directory they have group ownership on.

This parameter is best used with the inherit owner option and also on on a share containing directories with the UNIX setgid bit set on them, which causes new files and directories created within it to inherit the group ownership from the containing directory.

This is parameter has been was deprecated in Samba 3.0.23, but re-activated in Samba 3.0.31 and above, as it now only controls permission changes if the user is in the owning primary group. It is now no longer equivalent to the dos filemode option.

Default: acl group control = no

acl map full control (S)

This boolean parameter controls whether smbd(8) maps a POSIX ACE entry of "rwx" (read/write/execute), the maximum allowed POSIX permission set, into a Windows ACL of "FULL CONTROL". If this parameter is set to true any POSIX ACE entry of "rwx" will be returned in a Windows ACL as "FULL CONTROL", is this parameter is set to false any POSIX ACE entry of "rwx" will be returned as the specific Windows ACL bits representing read, write and execute.

Default: acl map full control = True

add group script (G)

This is the full pathname to a script that will be run AS ROOT by smbd(8) when a new group is requested. It will expand any %g to the group name passed. This script is only useful for installations using the Windows NT domain administration tools. The script is free to create a group with an arbitrary name to circumvent unix group name restrictions. In that case the script must print the numeric gid of the created group on stdout.

Default: add group script =

Example: add group script = /usr/sbin/groupadd %g

add machine script (G)

This is the full pathname to a script that will be run by smbd(8) when a machine is added to Samba´s domain and a Unix account matching the machine´s name appended with a "$" does not already exist.

This option is very similar to the add user script, and likewise uses the %u substitution for the account name. Do not use the %m substitution.

Default: add machine script =

Example: add machine script = /usr/sbin/adduser -n -g machines -c Machine -d /var/lib/nobody -s /bin/false %u

addport command (G)

Samba 3.0.23 introduced support for adding printer ports remotely using the Windows "Add Standard TCP/IP Port Wizard". This option defines an external program to be executed when smbd receives a request to add a new Port to the system. The script is passed two parameters:

· port name

· device URI

The deviceURI is in the format of socket://<hostname>[:<portnumber>] orlpd://<hostname>/<queuename>.

Default: addport command =

Example: addport command = /etc/samba/scripts/addport.sh

addprinter command (G)

With the introduction of MS-RPC based printing support for Windows NT/2000 clients in Samba 2.2, The MS Add Printer Wizard (APW) icon is now also available in the "Printers..." folder displayed a share listing. The APW allows for printers to be add remotely to a Samba or Windows NT/2000 print server.

For a Samba host this means that the printer must be physically added to the underlying printing system. The addprinter command defines a script to be run which will perform the necessary operations for adding the printer to the print system and to add the appropriate service definition to the smb.conf file in order that it can be shared by smbd(8).

The addprinter command is automatically invoked with the following parameter (in order):

· printer name

· share name

· port name

· driver name

· location

· Windows 9x driver location

All parameters are filled in from the PRINTER_INFO_2 structure sent by the Windows NT/2000 clientwith one exception. The "Windows 9x driver location" parameter is included for backwardscompatibility only. The remaining fields in the structure are generated from answers to the APWquestions.

Once the addprinter command has been executed, smbd will reparse the smb.conf to determine if theshare defined by the APW exists. If the sharename is still invalid, then smbd will return anACCESS_DENIED error to the client.

The addprinter command program can output a single line of text, which Samba will set as the portthe new printer is connected to. If this line isn´t output, Samba won´t reload its printer shares.

Default: addprinter command =

Example: addprinter command = /usr/bin/addprinter

add share command (G)

Samba 2.2.0 introduced the ability to dynamically add and delete shares via the Windows NT 4.0 Server Manager. The add share command is used to define an external program or script which will add a new service definition to smb.conf.

In order to successfully execute the add share command, smbd requires that the administrator connects using a root account (i.e. uid == 0) or has the SeDiskOperatorPrivilege. Scripts defined in the add share command parameter are executed as root.

When executed, smbd will automatically invoke the add share command with five parameters.

· configFile - the location of the global smb.conf file.

· shareName - the name of the new share.

· pathName - path to an **existing** directory on disk.

· comment - comment string to associate with the new share.

· max connections Number of maximum simultaneous connections to this share.

This parameter is only used to add file shares. To add printer shares, see the addprinter command.

Default: add share command =

Example: add share command = /usr/local/bin/addshare

add user script (G)

This is the full pathname to a script that will be run AS ROOT by smbd(8) under special circumstances described below.

Normally, a Samba server requires that UNIX users are created for all users accessing files on this server. For sites that use Windows NT account databases as their primary user database creating these users and keeping the user list in sync with the Windows NT PDC is an onerous task. This option allows smbd to create the required UNIX users ON DEMAND when a user accesses the Samba server.

When the Windows user attempts to access the Samba server, at login (session setup in the SMB protocol) time, smbd(8) contacts the password server and attempts to authenticate the given user with the given password. If the authentication succeeds then smbd attempts to find a UNIX user in the UNIX password database to map the Windows user into. If this lookup fails, and add user script is set then smbd will call the specified script AS ROOT, expanding any %u argument to be the user name to create.

If this script successfully creates the user then smbd will continue on as though the UNIX user already existed. In this way, UNIX users are dynamically created to match existing Windows NT accounts.

See also security, password server, delete user script.

Default: add user script =

Example: add user script = /usr/local/samba/bin/add_user %u

add user to group script (G)

Full path to the script that will be called when a user is added to a group using the Windows NT domain administration tools. It will be run by smbd(8) AS ROOT. Any %g will be replaced with the group name and any %u will be replaced with the user name.

Note that the adduser command used in the example below does not support the used syntax on all systems.

Default: add user to group script =

Example: add user to group script = /usr/sbin/adduser %u %g

administrative share (S)

If this parameter is set to yes for a share, then the share will be an administrative share. The Administrative Shares are the default network shares created by all Windows NT-based operating systems. These are shares like C$, D$ or ADMIN$. The type of these shares is STYPE_DISKTREE_HIDDEN.

See the section below on security for more information about this option.

Default: administrative share = no

admin users (S)

This is a list of users who will be granted administrative privileges on the share. This means that they will do all file operations as the super-user (root).

You should use this option very carefully, as any user in this list will be able to do anything they like on the share, irrespective of file permissions.

Default: admin users =

Example: admin users = jason

afs share (S)

This parameter controls whether special AFS features are enabled for this share. If enabled, it assumes that the directory exported via the path parameter is a local AFS import. The special AFS features include the attempt to hand-craft an AFS token if you enabled --with-fake-kaserver in configure.

Default: afs share = no

afs token lifetime (G)

This parameter controls the lifetime of tokens that the AFS fake-kaserver claims. In reality these never expire but this lifetime controls when the afs client will forget the token.

Set this parameter to 0 to get NEVERDATE.

Default: afs token lifetime = 604800

afs username map (G)

If you are using the fake kaserver AFS feature, you might want to hand-craft the usernames you are creating tokens for. For example this is necessary if you have users from several domain in your AFS Protection Database. One possible scheme to code users as DOMAIN+User as it is done by winbind with the + as a separator.

The mapped user name must contain the cell name to log into, so without setting this parameter there will be no token.

Default: afs username map =

Example: afs username map = %u@afs.samba.org

aio read size (S)

If Samba has been built with asynchronous I/O support and this integer parameter is set to non-zero value, Samba will read from file asynchronously when size of request is bigger than this value. Note that it happens only for non-chained and non-chaining reads and when not using write cache.

Current implementation of asynchronous I/O in Samba 3.0 does support only up to 10 outstanding asynchronous requests, read and write combined.

Related command: write cache size

Related command: aio write size

Default: aio read size = 0

Example: aio read size = 16384 # Use asynchronous I/O for reads bigger than 16KB request size

aio write behind (S)

If Samba has been built with asynchronous I/O support, Samba will not wait until write requests are finished before returning the result to the client for files listed in this parameter. Instead, Samba will immediately return that the write request has been finished successfully, no matter if the operation will succeed or not. This might speed up clients without aio support, but is really dangerous, because data could be lost and files could be damaged.

The syntax is identical to the veto files parameter.

Default: aio write behind =

Example: aio write behind = /*.tmp/

aio write size (S)

If Samba has been built with asynchronous I/O support and this integer parameter is set to non-zero value, Samba will write to file asynchronously when size of request is bigger than this value. Note that it happens only for non-chained and non-chaining reads and when not using write cache.

Current implementation of asynchronous I/O in Samba 3.0 does support only up to 10 outstanding asynchronous requests, read and write combined.

Related command: write cache size

Related command: aio read size

Default: aio write size = 0

Example: aio write size = 16384 # Use asynchronous I/O for writes bigger than 16KB request size

algorithmic rid base (G)

This determines how Samba will use its algorithmic mapping from uids/gid to the RIDs needed to construct NT Security Identifiers.

Setting this option to a larger value could be useful to sites transitioning from WinNT and Win2k, as existing user and group rids would otherwise clash with system users etc.

All UIDs and GIDs must be able to be resolved into SIDs for the correct operation of ACLs on the server. As such the algorithmic mapping can´t be ´turned off´, but pushing it ´out of the way´ should resolve the issues. Users and groups can then be assigned ´low´ RIDs in arbitrary-rid supporting backends.

Default: algorithmic rid base = 1000

Example: algorithmic rid base = 100000