bak dump(8dfs)

Dumps a specific fileset family at a specific dump level

Synopsis

bak dump -family fileset_family_name -level dump_level [-tcid tc_number]
[-noaction] [-help]

Options

-family fileset_family_name
Names the fileset family (already defined in the Backup Database using the bak addftfamily and bak addftentry commands) to be dumped.

-level dump_level
Indicates the dump level (already defined in the Backup Database using the bak adddump command) to be used in dumping the fileset family. Provide a full pathname for the dump level, including all necessary / (slashes). This option determines whether the dump is full or incremental and, in the latter case, determines which dump level serves as the parent for the dump.

-tcid tc_number
Specifies the Tape Coordinator ID (TCID) of the Tape Coordinator for the tape drive containing the tape. If omitted, it defaults to 0 (zero).

-noaction
Displays all filesets that would be included in the indicated dump without actually performing the dump. This lets you check a fileset family's size before actually dumping it so that you can calculate the correct number of tapes needed. Specify all other options as you would to actually perform the operation.

-help
Prints the online help for this command. All other valid options specified with this option are ignored.

Description
The bak dump command dumps the fileset family specified by -family at the dump level specified as a pathname by -level. There are two types of dumps:

· A full dump records the structure of all directories in each fileset in the fileset family and includes all the data in each fileset.

· An incremental dump also records the structure of all directories in each fileset in the fileset family, but it includes data from only those files in the filesets that changed since the fileset family was dumped at the parent dump level; such files have modification time stamps later than the date and time at which the fileset family was dumped at the parent dump level. The program uses the next-to-last element in the -level pathname as the parent dump and consults the Backup Database to learn the date and time at which this fileset family was last dumped at that level.

If the program cannot locate a dump set dumped at a parent dump level, it looks recursively in the Backup Database for a dump set created at the dump level one higher in the pathname. If it can find no dump set created at a higher dump level in the hierarchy, it creates a full dump set.

If the Backup System is unable to access a fileset (for example, because of a File Server machine or Fileset Server outage), it attempts to access the fileset three times over the course of the operation. If it cannot access the fileset after the third attempt, it omits the fileset from the dump instead of stopping the dump entirely. If the Tape Coordinator performing the dump was initialized at debug level 1, a report on the failure to include the fileset appears in the Tape Coordinator's monitoring window. The Tape Coordinator's error file also records the fileset's omission.

If the failure to access a fileset occurs during a full dump, the next incremental dump of the fileset includes the entire fileset. If the failure occurs during an incremental dump, the next incremental dump of the fileset includes all files modified since the fileset was last included in a dump set.

Before writing the dump to tape, the Tape Coordinator checks that the tape in the indicated tape drive has an acceptable name on its label. If the name on the label is not acceptable, the Backup System prompts for the correct tape. There are three acceptable types of names:

· The tape is labeled fileset_family_name.dump_level.index, where fileset_family_name and dump_level match the values provided on the command line (with -family and -level). The dump_level is the last component of the specified dump level; the index distinguishes this tape from others that contain this same dump set. If a single tape contains the entire dump set, its index is 1.

· The tape is labeled as empty. The Backup System labels the tape with the correct name of the form fileset_family_name.dump_level.index.

· The tape is not labeled because it has never been used in the Backup System. The Backup System labels the tape with the correct name of the form fileset_family_name.dump_level.index.

If it finds that the name on the tape label is acceptable, the Backup System checks the expiration date on the tape before it writes data to it. If the expiration date has not expired, the system does not write data to the tape unless the issuer relabels the tape with the bak labeltape command (because the label records the expiration date, erasing the label removes the obstacle to overwriting). If the expiration date has expired or if no expiration date is associated with the tape, the system overwrites the contents of the tape without question (given that the tape has an acceptable name).

The tape label also tells the Tape Coordinator the size of the tape. However, the Tape Coordinator applies the capacity specified in the TapeConfig file for the tape drive containing the tape to any tape, regardless of the size specified in the tape's label. Make sure the tapes are at least as large as the tape size listed in the TapeConfig file. If a tape is larger, some of its capacity simply may not be used for the dump; if it is smaller, the dump may fail, but only after the Backup System fills the tape and determines that the tape is too small for the drive.

The Backup System does not require that a fileset fit entirely on a single tape. If the Tape Coordinator reaches the end of a tape while dumping a fileset, it puts the remaining data onto the next tape. The Backup Database automatically records that the fileset is on multiple tapes.

The -noaction option instructs the program to display a list of the filesets to be included in a dump set without actually performing the dump. This allows the issuer to determine how large the filesets are before actually dumping them; the issuer can then better calculate the required number of tapes. The command ignores a value specified with the -tcid option if the -noaction option is used with the command.

The bak restoreft, bak restoredisk, and bak restoreftfamily commands can be used to restore data dumped with the bak dump command. You can use the commands to restore data to any type of file system (DCE LFS or non-LFS), regardless of the type of file system from which it was dumped. Thus, you can dump and restore data between DCE LFS and non-LFS file systems, as well as between different types of non-LFS file systems. (See the documentation for the bak restoreft, bak restoredisk, and bak restoreftfamily commands for more information about dumping and restoring data between different types of file systems.)

Privilege Required
The issuer must be listed in the admin.bak files on all Backup Database machines. The issuer must also be listed in the admin.fl files on all Fileset Database machines and in the admin.ft files on all File Server machines from which filesets are to be dumped.

Output
The following header is displayed in the command window followed by a list of the filesets, identified by name and fileset ID number, to be included in the dump set:

Preparing to dump the following filesets: list of filesets

The following message indicates that the Backup System has passed the dump request to the indicated Tape Coordinator:

Starting dump.

It is followed by a message that reports the unique dump ID number associated with this dump operation:

Dump ID of dump fileset_family_name.dump_level: dump_ID_number

The dump ID also appears in the Tape Coordinator monitoring window if the butc command is issued with debug level 1. The dump ID is not the same as the job ID number visible with (bak) jobs when bak dump is issued in interactive mode.

If the issuer includes the -noaction option, the output is

Starting dump of fileset family 'fileset family' (dump level 'dump level')

Total number of filesets : number

Would have dumped the following filesets:

list of filesets

Examples
The following command dumps the filesets in the fileset family user according to the dump level /full/week2/monday. The issuer places the necessary tapes in the drive with TCID 5.

$ bak dump user /full/week2/monday 5

Preparing to dump the following filesets:

user.jones.bak 387623900

user.pat.bak 486219245

user.smith.bak 597315841

Starting dump.

Dump ID of dump user.monday: 34

The following command displays the list of filesets to be dumped when the sys.rs_aix32 fileset family is dumped at the /full dump level:

$ bak dump sys.rs_aix32 /full -n

Starting dump of fileset family 'sys.rs_aix32' (dump level '/full')

Total number of filesets : 24

Would have dumped the following filesets: