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VOS(1) AFS Command Reference VOS(1)


vos - Introduction to the vos command suite


The commands in the vos command suite are the administrative interface to the Volume Server and Volume Location (VL) Server. System administrators use vos commands to create, move, delete, replicate, back up and examine volumes, among other operations. The VL Server automatically records in the Volume Location Database (VLDB) changes in volume status and location that result from vos commands.

The operations invoked by most vos commands are idempotent, meaning that if an operation is interrupted by a network, server machine, or process outage, then a subsequent attempt at the same operation continues from the interruption point, rather than starting over at the beginning of the operation. Before executing a command, the Volume and VL Servers check the current state of the volumes and VLDB records to be altered by the command. If they are already in the desired end state (or a consistent intermediate state), there is no need to repeat the internal steps that brought them there. Idempotency does not apply if the command issuer explicitly interrupts the operation with the Ctrl-C command or another interrupt signal. In that case, the volume is left locked and the administrator must use the vos unlock command to unlock it before proceeding.

It is important that the VLDB accurately indicate the status of the volumes on file server machines at all times. vldb.DB0(5) and afs_volume_header(5) describe the information recorded in the VLDB and volume headers, respectively. If a vos command changes volume status, it automatically records the change in the corresponding VLDB entry. The most common cause of discrepancies between the VLDB and volume status on file server machines is interrupted operations; to restore consistency, use the vos syncserv and vos syncvldb commands.

There are several categories of commands in the vos command suite:

  • Commands to create, move, and rename volumes: vos backup, vos backupsys, vos changeloc, vos create, vos move, and vos rename.
  • Commands to remove VLDB volume records or volumes or both: vos delentry, vos remove, and vos zap.
  • Commands to edit or display VLDB server entries: vos changeaddr, vos listaddrs vos setaddrs, and vos remaddrs.
  • Commands to create, size, and restore dump files: vos dump, vos restore, and vos size.
  • Commands to administer replicated volumes: vos addsite, vos release, and vos remsite.
  • Commands to display VLDB records, volume headers, or both: vos examine, vos listvldb, and vos listvol.
  • Commands to display information about partitions that house volumes: vos listpart and vos partinfo.
  • Commands to restore consistency between the VLDB and volume headers: vos syncserv and vos syncvldb.
  • Commands to lock and unlock VLDB entries: vos lock, vos unlock, and vos unlockvldb.
  • A command to report Volume Server status: vos status.
  • A command to end Volume Server transactions: vos endtrans.
  • A command to change volume fields: vos setfields.
  • Commands to obtain help: vos apropos and vos help.


Currently, the maximum quota for a volume is 2 terabytes (2^41 bytes). Note that this only affects the volume's quota; a volume may grow much larger if the volume quota is disabled. However, volumes over 2 terabytes in size may be impractical to move, and may have their size incorrectly reported by some tools, such as fs_listquota(1).


The following arguments and flags are available on many commands in the vos suite. The reference page for each command also lists them, but they are described here in greater detail.

Names the cell in which to run the command. It is acceptable to abbreviate the cell name to the shortest form that distinguishes it from the other entries in the /etc/openafs/CellServDB file on the local machine. If the -cell argument is omitted, the command interpreter determines the name of the local cell by reading the following in order:
  • The value of the AFSCELL environment variable.
  • The local /etc/openafs/ThisCell file.

Do not combine the -cell and -localauth options. A command on which the -localauth flag is included always runs in the local cell (as defined in the server machine's local /etc/openafs/server/ThisCell file), whereas a command on which the -cell argument is included runs in the specified foreign cell.

The location of the directory to use to obtain configuration information, including the CellServDB. This is primarily provided for testing purposes.
Prints a command's online help message on the standard output stream. Do not combine this flag with any of the command's other options; when it is provided, the command interpreter ignores all other options, and only prints the help message.
Constructs a server ticket using the server encryption key with the highest key version number in the local /etc/openafs/server/KeyFile file. The vos command interpreter presents the ticket, which never expires, to the Volume Server and VL Server during mutual authentication.

Use this flag only when issuing a command on a server machine; client machines do not usually have a /etc/openafs/server/KeyFile file. The issuer of a command that includes this flag must be logged on to the server machine as the local superuser "root". The flag is useful for commands invoked by an unattended application program, such as a process controlled by the UNIX cron utility or by a cron entry in the machine's /etc/openafs/BosConfig file. It is also useful if an administrator is unable to authenticate to AFS but is logged in as the local superuser root.

Do not combine the -cell and -localauth options. A command on which the -localauth flag is included always runs in the local cell (as defined in the server machine's local /etc/openafs/server/ThisCell file), whereas a command on which the -cell argument is included runs in the specified foreign cell. Also, do not combine the -localauth and -noauth flags.

Establishes an unauthenticated connection to the Volume Server and VL Server, in which the servers treat the issuer as the unprivileged user "anonymous". It is useful only when authorization checking is disabled on the server machine (during the installation of a file server machine or when the bos setauth command has been used during other unusual circumstances). In normal circumstances, the servers allow only privileged users to issue commands that change the status of a volume or VLDB record, and refuses to perform such an action even if the -noauth flag is provided. Do not combine the -noauth and -localauth flags.
Identifies the AFS server partition on a file server machine that houses, or is to house, the volumes of interest, or about which to list information. The vos command interpreter accepts any of the following four name formats:

   /vicepa     =     vicepa      =      a      =      0
   /vicepb     =     vicepb      =      b      =      1

After /vicepz (for which the index is 25) comes

   /vicepaa    =     vicepaa     =      aa     =      26
   /vicepab    =     vicepab     =      ab     =      27

and so on through

   /vicepiv    =     vicepiv     =      iv     =      255

The -frompartition and -topartition arguments to the vos move command also accept this notation.

Identifies the file server machine that houses, or is to house, the volumes or AFS server partitions of interest. Provide the machine's IP address in dotted decimal format, its fully qualified host name (for example, ""), or the shortest abbreviated form of its host name that distinguishes it from other machines. Successful use of an abbreviated form depends on the availability of a name resolution service (such as the Domain Name Service or a local host table) at the time the command is issued.

The -fromserver and -toserver arguments to the vos move command also accept these name formats.

Shows all servers as IP addresses instead of the DNS name. This is very useful when the server address is registered as or when dealing with multi-homed servers. The -noresolve option is available in OpenAFS versions 1.4.8 or later and 1.5.35 or later.
Produces on the standard output stream a detailed trace of the command's execution. If this argument is omitted, only warnings and error messages appear.


To issue most vos commands, the issuer must be listed in the /etc/openafs/server/UserList file on each server machine that houses or is to house an affected volume, and on each database server machine. The most predictable performance results if all database server and file server machines in the cell share a common UserList file. Alternatively, if the -localauth flag is included, the issuer must be logged on to a server machine as the local superuser "root".

To issue a vos command that only displays information, no privilege is required.


vos_addsite(1), vos_apropos(1), vos_backup(1), vos_backupsys(1), vos_changeaddr(1), vos_convertROtoRW(1), vos_clone(1), vos_copy(1), vos_create(1), vos_delentry(1), vos_dump(1), vos_endtrans(1), vos_examine(1), vos_help(1), vos_listaddrs(1), vos_listpart(1), vos_listvldb(1), vos_listvol(1), vos_lock(1), vos_move(1), vos_partinfo(1), vos_release(1), vos_remove(1), vos_remsite(1), vos_rename(1), vos_restore(1), vos_setfields(1), vos_shadow(1), vos_size(1), vos_status(1), vos_syncserv(1), vos_syncvldb(1), vos_unlock(1), vos_unlockvldb(1), vos_zap(1), CellServDB(5), UserList(5)


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This documentation is covered by the IBM Public License Version 1.0. It was converted from HTML to POD by software written by Chas Williams and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.

2021-01-14 OpenAFS