vxdump - incremental file system dump


vxdump [ -nuwW ] [ -0123456789 ] [ -f file_name] [ -d density] [ -s size] [ -T time] [ -b block_size]
[ -B records] filesystem

vxdump [option [argument...] filesystem]


vxdump copies to magnetic tape all files in the vxfs filesystem that have been changed after a certain date. This information is derived from the files /etc/dumpdates and /etc/vfstab.

vxdump supports both getopt(S) and traditional ufsdump(ADM) command line invocations as shown above. The original ufsdump command line style is supported for compatibility with previous versions of vxdump and for synonymy with the existing ufsdump program used for ufs file systems. For the traditional command line style, option consists of characters from the set 0123456789bBdfnsTuWw without any intervening white space.

On most devices vxdump can detect end-of-media and prompt for the media to be changed, so it is not necessary to specify the size of the device. However, if the dump will require multiple tapes and the tapes are to be read using an older version of vxrestore(ADM), or if the tape device handles end-of-media in a way that vxdump doesn't understand, then the size of the device must be specified using either the -B option or a combination of the -d and -s options.


Where number is in the range [0-9]. This number is the dump level. All files modified since the last date stored in the file /etc/dumpdates for the same file system at a lesser dump level will be dumped. Thus, the option -0 causes the entire file system to be dumped. If no date is determined by the level, the beginning of time is assumed.

-B records
The number of logical records per volume. The vxdump logical record size is 1024 bytes. records can also be specified with a suffix to indicate a unit of measure other than 1024 bytes. A k, m, or g can be appended to the number to indicate that the value is in kilobytes, megabytes, or gigabytes, respectively. This option overrides the calculation of tape size based on length and density.

-b block_size
The blocking factor is taken from the block_size option argument. (default is 63 if -b is not specified). Block size is defined as the logical record size times the blocking factor. vxdump writes logical records of 1024 bytes. Older versions of vxdump used a blocking factor of 10 for tapes with densities less than 6250 BPI, and 32 for tapes with densities of 6250 BPI or greater. vxrestore (see vxrestore(ADM)) will dynamically determine the blocking factor.

-d density
The density of the tape (expressed in BPI). This is used in calculating the amount of tape used per tape reel. If the -s option is specified, a default density value of 1600 is assumed a for a reel tape.

-f file_name
Place the dump on the file file_name instead of the tape. If the name of the file is -, vxdump writes to the standard output. This option can be of the form machine:device to specify a tape device on a remote machine.

Whenever vxdump requires operator attention, notify all users in group operator by means similar to that described by wall(ADM).

-s size
size is the size of the dump tape, specified in feet. When the specified size is reached, vxdump waits for reels to be changed. If the -d option is specified, a default size value of 2300 is assumed a for a reel tape.

If the dump completes successfully, write on file /etc/dumpdates the date when the dump started. This file records a separate date for each file system and each dump level. The format of / etc/dumpdates is user-readable and consists of one free-format record per line: file system name, increment level and dump date in ctime(S) format. The file /etc/dumpdates can be edited to change any of the fields if necessary.

-T date
Use the specified date as the starting time for the dump instead of the time determined from looking in /etc/dumpdates. The format of date is the same as that of ctime(S). This option is useful for automated dump scripts that wish to dump over a specific period of time. The -T option is mutually exclusive with the -u option.

For each file system in /etc/dumpdates, print the most recent dump date and level, indicating which file systems should be dumped. If the -W option is set, all other options are ignored and vxdump exits immediately.

Operates like W, but prints only file systems that need to be dumped.

If no arguments are given, the options are assumed to be -9u and a default file system is dumped to the default tape.

Operator interaction

vxdump requires operator intervention for any of the following conditions:

In addition to alerting all operators implied by the -n option, vxdump interacts with the control terminal operator by posing questions requiring yes or no answers when it can no longer proceed or if something is grossly wrong.

Since making a full dump involves considerable time and effort, vxdump establishes a checkpoint at the start of each tape volume. If, for any reason, writing that volume fails, vxdump will, with operator permission, restart from the checkpoint after the old tape has been rewound and removed and a new tape has been mounted.

vxdump periodically reports information to the operator, including estimates (typically low) of the number of blocks to write, the number of tapes it will require, time needed for completion, and the time remaining until tape change. The output is verbose to inform other users that the terminal controlling vxdump is busy and will be for some time.


The dump tape format is independent of the VxFS disk layout. A dump of a file system with the Version 4 disk layout can be restored on a file system using the Version 2 disk layout or even a file system of another file system type, with the following exceptions:

If you use vxdump to produce a dump intended for an earlier version of vxrestore, and if the dump requires multiple tapes, you should use the -s, -d, or -B option.

Dumps produced by older versions of vxdump can be read by the current version of vxrestore.

Tapes produced by vxdump on other platforms can also be read by vxrestore, provided they are not from a version of vxdump more recent the version of vxrestore in use (see vxrestore(ADM)).


Dumps should be performed with the file system unmounted or the system in single-user environment (see init(ADM)) to insure a consistent dump. If the VxFS Advanced feature set is enabled, the dump can be performed in the multi-user environment using a snapshot file system with the online backup facility (see the snapof=file option of mount(ADM)).

Up to 32 read errors on the file system are ignored.

Each reel requires a new process; thus parent processes for reels already written remain until the entire tape is written.

The vxdump and vxrestore commands are fully interoperable with the dump and restore commands: tapes created by vxdump can be restored by restore; and tapes created by dump can be restored by vxrestore (see vxrestore(ADM)).


In the following example, assume that the file system /mnt is normally attached to the file tree at the root (/) directory.

This example causes the entire file system (/mnt) to be dumped on /dev/ctape1 and specifies that the the size of the tape is 2 gigabytes.

vxdump -0 -B 2g -f /dev/ctape1 /mnt

Or, using the traditional command line syntax and specifying the tape size in logical records:

vxdump 0Bf 2097152 /dev/ctape1 /mnt

where the option argument "2097152" goes with the option letter B as it is the first option letter that requires an option argument, and where the option argument "/dev/ctape1" goes with the option letter f as it is the second option letter that requires an option argument.


vxdump is based on the dump program from the 4.4 Berkeley Software Distribution, developed by the the University of California, Berkeley, and its contributors.


Default tape unit to dump to.

New format-dump-date record.

Table of file system defaults.

Table of mounted file systems.

Used to find group operator.


setext(C), init(ADM), mount(ADM), ufsdump(ADM), vxrestore(ADM), wall(ADM), ctime(S), getopt(S), vfstab(F)

Copyright © 2005 The SCO Group, Inc. All rights reserved.