vos_dump - Converts a volume into ASCII format and writes it to a file


vos dump -id <volume name or ID> [-time <dump from time>] [-file <dump file>] [-server <server>] [-partition <partition>] [-clone] [-omitdirs] [-cell <cell name>] [-noauth] [-localauth] [-verbose] [-encrypt] [-noresolve] [-help]

vos du -i <volume name or ID> [-t <dump from time>] [-f <dump file>] [-s <server>] [-p <partition>] [-cl] [-o] [-ce <cell name>] [-noa] [-l] [-v] [-e] [-nor] [-h]


The vos dump command converts the contents of the indicated volume, which can be read/write, read-only or backup, into ASCII format. The Volume Server writes the converted contents to the file named by the -file argument, or to the standard output stream. In the latter case, the output can be directed to a named pipe, which enables interoperation with third-party backup utilities.

To dump the complete contents of a volume (create a full dump), omit the -time argument or specify the value 0 (zero) for it. To create an incremental dump, which includes only the files and directories in the volume that have modification timestamps later than a certain time, specify a date and time as the value for the -time argument.

By default, the vos command interpreter consults the Volume Location Database (VLDB) to learn the volume's location, so the -server and -partition arguments are not required. If the -id argument identifies a read-only volume that resides at multiple sites, the command dumps the version from just one of them (normally, the one listed first in the volume's VLDB entry as reported by the vos examine or vos listvldb command). To dump the read-only volume from a particular site, use the -server and -partition arguments to specify the site. To bypass the VLDB lookup entirely, provide a volume ID number (rather than a volume name) as the value for the -id argument, together with the -server and -partition arguments. This makes it possible to dump a volume for which there is no VLDB entry.

During the dump operation, the volume is inaccessible both to Cache Managers and to other volume operations. Dumping a volume does not otherwise affect its status on the partition or its VLDB entry.

To restore a dumped volume back into AFS, use the vos restore command.


Support for incremental dumps is provided to facilitate interoperation with third-party backup utilities. The vos dump command does not provide any of the administrative facilities of an actual backup system, so the administrator must keep manual records of dump times and the relationship between full and incremental dumps of a volume. For a volume's contents to be consistent after restoration of incremental dumps, there must be no gap between the time at which a prior dump of the volume was created and the value of the -time argument to the vos dump command that creates the incremental dump. More specifically, for a read/write volume, the -time argument must specify the time that the prior dump was performed, and for a read-only or backup volume it must specify the time that the volume was last released (using the vos release command) or cloned (using the vos backup or vos backupsys command) prior to dumping it. The parent dump can be either a full dump or another incremental dump.


-id <volume name or ID>

Specifies either the complete name or volume ID number of the read/write, read-only, or backup volume to dump.

-time <dump from time>

Specifies whether the dump is full or incremental. Omit this argument to create a full dump, or provide one of three acceptable values:

-file <dump file>

Specifies the pathname of the file to which to write the dump. The file can be in AFS, but not in the volume being dumped. A partial pathname is interpreted relative to the current working directory. If this argument is omitted, the dump is directed to the standard output stream.

-server <server name>

Specifies the file server machine on which the volume resides. Provide the -partition argument along with this one.

-partition <partition name>

Specifies the partition on which the volume resides. Provide the -server argument along with this one.


Normally, vos dump locks the volume and dumps it, which blocks writes to the volume while the dump is in progress. If this flag is given, vos dump will instead clone the volume first (similar to what vos move would do) and then dumps the clone. This can significantly decrease the amount of time the volume is kept locked for dumps of large volumes.


By default, vos dump includes all directory objects in an incremental dump whether they've been changed or not. If this option is given, unchanged directories will be omitted. This will reduce the size of the dump and not cause problems if the incremental is restored, as expected, on top of a volume containing the correct directory structure (such as one created by restoring previous full and incremental dumps).

-cell <cell name

Names the cell in which to run the command. Do not combine this argument with the -localauth flag. For more details, see vos(1).


Assigns the unprivileged identity anonymous to the issuer. Do not combine this flag with the -localauth flag. For more details, see vos(1).


Constructs a server ticket using a key from the local /usr/afs/etc/KeyFile file. The vos command interpreter presents it to the Volume Server and Volume Location Server during mutual authentication. Do not combine this flag with the -cell argument or -noauth flag. For more details, see vos(1).


Produces on the standard error stream a detailed trace of the command's execution. If this argument is omitted, only warnings and error messages appear.


Encrypts the command so that the operation's results are not transmitted across the network in clear text. This option is available in OpenAFS versions 1.4.11 or later and 1.5.60 or later.


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. This option is available in OpenAFS versions 1.4.8 or later and 1.5.35 or later.


Prints the online help for this command. All other valid options are ignored.


The following command writes a full dump of the volume user.terry to the file /afs/

   % vos dump -id user.terry -time 0 -file /afs/

The following command writes an incremental dump of the volume user.smith to the file smith.990131.dump in the current working directory. Only those files in the volume with modification time stamps later than 6:00 p.m. on 31 January 1999 are included in the dump.

   % vos dump -id user.smith -time "01/31/1999 18:00" -file smith.990131.dump


The issuer must be listed in the /usr/afs/etc/UserList file on the machine specified with the -server argument and on each database server machine. If the -localauth flag is included, the issuer must instead be logged on to a server machine as the local superuser root.

If the -file argument is included, the issuer must also have permission to insert and write in the directory that houses the file.


restorevol(1), vos(1), vos_examine(1), vos_listvldb(1), vos_restore(1)


IBM Corporation 2000. <> All Rights Reserved.

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.