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Command Reference A-29
NAME
dump - file system backup
SYNOPSIS
dump [
options
[
arguments
] ]
subtree
DESCRIPTION
The dump command examines files in a subtree and writes to tape the files that
need to be backed up. The Data ONTAP 5.3 dump command differs slightly from
the standard UNIX dump, but the output format is compatible with SunOS 4.x/
Solaris 1.x and SunOS 5.x/Solaris 2.x dump.
Data ONTAP 5.3 dump can write to its standard output (most useful with rsh
from a UNIX system), to a remote tape device on a host that supports the rmt
remote tape protocol or to a local tape drive, connected directly to the system
(tape).
The
subtree
argument specifies a subtree to be dumped. This is one way to allow
dump to work with remote tape devices that are limited to 2 GB of data per tape
file. The specified
subtree
may be in the active file system (e.g. /home) or in a
snapshot (e.g. /.snapshot/weekly.0/home). If the subtree is in the active file
system, dump creates a snapshot named snapshot_for_dump.X where X is a
sequentially incrementing integer. This naming convention prevents conflicts
between concurrently executing dumps. The dump is run on this snapshot so
that its output will be consistent even if the filer is active. If dump does create a
snapshot, it automatically deletes the snapshot when it completes.
Another way to allow dump to work with remote tape devices that are limited to
2 GB of data per tape file is to dump to multiple tape files or volumes. The B
option to dump specifies the maximum amount of data to be dumped to one vol-
ume; when that much data has been written to one volume, dump will start
writing to another volume. A list of tape devices can be specified as arguments
to the f option, and the volumes will be written to the devices in that list, in order.
If there are no more devices in the list, dump will re-use the last device in the
list, after prompting the user to indicate that theyve put a new tape in that
device.
The Data ONTAP 5.3 dump command handling of end of tape is slightly different
than that of the standard UNIX dump. Instead of aborting the entire dump if EOT
is reached, the Data ONTAP5.3 dump starts a new volume and continues the
dump on the next tape. Specifying a large value for the B option will cause dump
to utilize the entire tape.
You can enter the dump command on a trusted host through rsh. It is preferable
to enter the dump command through rsh if the backup takes a significant
amount of time. This is because if you enter the dump command on the console,
the filer does not display the console prompt until the backup is finished. During
the time when the filer is backing up data, you do not have console access to the
filer.
dump