NAME

vdump −  performs incremental fileset backups

SYNOPSIS

/sbin/vdump [−0..9] [−CDNVhquvw] [−F num_buffers]
[−T tape_num] [−b size] [−f device]
[−x num_blocks] fileset

filesetSpecifies the full path name of the directory, fileset, or file system that is backed up to the storage medium.  In this reference page, the term "fileset" also refers to UFS directories and file systems. 

FLAGS

−0..9Specifies the backup level. The value 0 for this flag causes the entire fileset to be backed up to the storage medium.  The default backup level is 9. 

−CCompresses the data as it is backed up, which minimizes the saveset size. 

−DBacks up the specified subdirectory of a fileset to the storage medium.  With this flag, the level specification is ignored.  A level 0 backup is run regardless of the level that is specified.  Without the −D flag, the vdump command backs up the entire file system that contains the subdirectory. 

−NDoes not rewind the tape. 

−VDisplays the current vdump version. 

−hDisplays usage help for the vdump command. 

−qDisplays only error messages; does not display information messages. 

−uUpdates the /etc/vdumpdates file with a timestamp entry from the beginning of the backup. 

−vDisplays the names of the files being backed up. 

−wDisplays the filesets that have not been backed up within one week. The −w flag does not require a specified fileset. 

−F num_buffers
Specifies the number of in-memory buffers to use.  The valid range is 1 through 64 buffers; the default is 8 buffers.

−T tape_num
Specifies the starting number for the first tape. The default number is 0.

−b sizeSpecifies the number of blocks in 1024-byte units.  The valid range is 1 through 64 blocks; the default is 60 blocks. 

−f device
Specifies the destination of the saveset, which can be a device, file, or - (dash).

−x num_blocks
Offers additional protection against saveset errors. An "exclusive or" (XOR) operation is performed on the number of blocks specified. This allows vrestore to recover one of the blocks in the group if a read error occurs.  The valid range is 2 through 32 blocks; the default is 8 blocks.  Note that the −x flag creates larger savesets and increases the amount of time required to back up a file system. 

DESCRIPTION

The vdump command backs up local files from a single fileset, defined by fileset, to a local storage device.  The vdump command is the backup facility for AdvFS; however, since the vdump command is file-system independent, you can use its additional features with other filesystems such as UFS. 

The vdump command copies all files in the specified local fileset that are new or have changed after a certain date to the default storage device (/dev/rmt0h).  The date is determined by comparing the specified backup level to previous backup levels recorded in the /etc/vdumpdates file.  An alternate storage device can be specified with the −f flag. 

The vdump command performs either an incremental backup, level 9 to 1, or a full backup, level 0, depending on the desired level of backup and the level of previous backups recorded in the /etc/vdumpdate file. 

The vdump command backs up all files that are new or have changed since the latest backup date of all backup levels that are lower than the backup level being performed.  If a backup level that is lower than the specified level does not exist, the vdump command initiates a level 0 backup.  A level 0 backup, which is called the Epoch, backs up all files. 

A typical /etc/vdumpdates file includes entries like the following, defining the fileset name, last backup level, and date:

dmn2#set2 8 wed Mar  3 07:40:35 1993
dmn2#set2 9 Thu Mar  4 07:20:42 1993
dmn2#set2 3 Fri Mar  5 07:47:37 1993
dmn2#set2 7 Thu Mar  4 08:23:05 1993
/dev/rz0g 0 Mon Mar  8 12:11:42 1993

In this example, dmn2#set2 represents an AdvFS fileset; /dev/rz0g represents a UNIX file system.  If you perform a level 8 backup of the dmn2#set2, using this /etc/vdumpdates file, you can expect the following results:

       •The vdump command ignores the /dev/rz0g entry, since it does not match the specified fileset, dmn2#set2. 

       •The vdump command ignores the level 8 and 9 entries, since these entries are equal to or higher than the level 8 backup you requested.  This leaves only the level 3 and 7 entries. 

       •Of the two remaining entries, the vdump command chooses the entry with the most recent dump date, which is the level 3 entry. 

       •The vdump command backs up all files that were created or modified after the dump date of the level 3 entry. 

When you specify the −u flag, the vdump command enters a time-stamp entry of that fileset and its backup level into the /etc/vdumpdates file. 

If a file-system entry with a specific backup level does not already exist in the /etc/vdumpdates file, the vdump command appends the file with a new vdump record; otherwise, the vdump command overwrites the existing record, changing the backup date to reflect the most current backup session. This occurs after all files in the named fileset are successfully backed up. 

NOTE

The vdump command modifies the access time of each file in the fileset. 

RESTRICTIONS

The /etc/vdumpdates file is written in ASCII and consists of a single record per line.  You must have root-user privilege to update this file or to change any record field. 

If you edit the /etc/vdumpdates file, be certain that all records follow the correct format.  An incorrectly formatted record in this file may make the file inaccessible for updates or reads. 

EXAMPLES

       •To perform a full level 0 backup, enter a command similar to the following:

% vdump −0 −u −f /dev/rmt1h /fs1

In this example, −0 specifies that all files in the fileset fs1 will be backed up to /dev/rmt1h; −u specifies vdump to update the /etc/vdumpdates after a successful backup of the fileset.  The output block size is set to 32 kilobytes. 

       •When the backup saveset device is the character − (dash), the vdump command writes to standard output.  Thus, the vdump and vrestore commands may be used in a pipeline expression to copy filesets.  The following are typical commands, both are equivalent:

# vdump −0 −f − /usr | (cd /mnt; vrestore −x −f −)
# vdump −0f − /usr | vrestore −xf − −D /mnt

       •For weekly tape backups, a set of 5 tapes per backed up fileset is also used on a cyclical basis.  Each month a level 0 backup is taken on a set of fresh tapes that are saved until the next level 0 backup. 

       •The following is a guideline for the level of backup to perform during weekly, biweekly, and monthly periods. 

FILES

/sbin/vdumpThe vdump command with static libraries. 

/etc/vdumpdatesContains a list of filesets that were backed up, the date that each file system was backed up, and the backup level. 

RELATED INFORMATION

vrestore(8), mt(1).