dump

July 7th, 2009

SYNOPSIS

dump options [ arguments ... ] tree

The dump command examines files in tree and writes to tape the files that need to be backed up. The Data ONTAP dump command differs slightly from the standard UNIX dump, but the output format is compatible with Solaris ufsrestore.

Data ONTAP 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(8) remote tape protocol, or to a local tape drive connected directly to the system (see tape ).

The tree argument specifies a volume, qtree, or other path name to be dumped. The specified tree may be in the active file system (e.g. /vol/vol0/home) or in a snapshot (e.g. /vol/vol0/.snapshot/weekly.0/home). If the tree 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.

If you do not explicitly name the volume of the dump (with the /vol prefix on the tree argument), the root volume is assumed to be specified.

OPTIONS

If characters in the options string take an arguments, the arguments (which follow the options string) are specified in the order of the letters which apply to them. For example:

dump 0ufb – 63 /vol/vol0

Here, dump uses two letters which take arguments: the `f’ and `b’ options. In this case, the “-” argument applies to `f’, and the “63” argument applies to `b’. (The “/vol/vol0” argument is, of course, the tree to be dumped.)

The following characters may be used to determine the behavior of dump.

0-9: Dump levels. A level 0, full backup, guarantees the entire file system is copied. A level number above 0, incremental backup, tells dump to copy all files new or modified since the last dump of a lower level.

The default dump level is 0.

A: Ignore Access Control Lists (ACLs) metadata during dump. Ordinarily, dump writes out metadata related to Windows ACLs. (And restore recovers those properties when creating shares, files, and directories.) This option prevents dump from writing out this information to the dump file.

B blocks
Set the size of the dump file to the specified number of 1024-byte blocks. If this amount is exceeded, dump closes the current file and opens the next file in the list specified by the f option. If there are no more files in that list, dump re-opens the last file in the list, and prompts for a new tape to be loaded.

It is recommended to be a bit conservative when using this option.

The `B’ flag is one way to allow dump to work with remote tape devices that are limited to 2 GB of data per tape file.

Q: Ignore files and directories in qtrees. If you create qtrees with the qtree command, the Q option makes it so that any files and/or directories under these qtrees will not be dumped.

This option only works on a level-0 dump.

X filelist
Specifies an exclude list, which is a comma-separated list of strings. If the name of a file matches one of the strings, it is excluded from the backup. The following list describes the rules for specifying the exclude list:

The name of the file must match the string exactly.

An asterisk is considered a wildcard character.

The wildcard character must be the first or last character of the string. Each string can contain up to two wildcard characters.

If you want to exclude files whose names contain a comma, precede the comma in the string with a backslash.

You can specify up to 32 strings in the exclude list.

b factor
Set the tape blocking factor in k-bytes. The default is 63 KB. NOTE: Some systems support blocking factors greater than 63 KB by breaking requests into 63-KB chunks or smaller using variable sized records; other systems do not support blocking factors greater than 63 KB at all. When using large blocking factors, always check the system(s) where the potential restore might occur to ensure that the blocking factor specified in dump is supported. On Solaris systems, the supported blocking factor information can be found in the ufsdump(1M) and ufsrestore(1M) man pages. Data ONTAP restricts the blocking factor for local tape devices to less than, or equal to, 64 KB. Therefore larger blocking factors should not be used on remote tape devices if you may want to restore the data on the tape from a local tape device.

f files Write the backup to the specified files. files may be:

A list of the names of local tape devices, in the form specified in tape .

A list of the names of tape devices on a remote host, in the form host:devices.

The standard output of the dump command, specified as -.

If the user specifies a list of devices, the list may have a single device or a comma-separated list of devices; note that the list must either contain only local devices or only devices on a remote host. In the latter case, the list must refer to devices on one particular remote host, e.g.

tapemachine:/dev/rst0, /dev/rst1

Each file in the list will be used for one dump volume in the order listed; if the dump requires more volumes than the number of names given, the last file name will be used for all remaining volumes. In this case, the dump command at the console will prompt the user for media changes.

Use sysconfig -t for a list of local tape devices. See the EXAMPLES section below for an example of a dump to local tape.

For a dump to a tape device on a remote host, the host must support the standard UNIX rmt(8) remote tape protocol.

By default, dump writes to standard output.

l: Specifies that this is a multi-subtree dump. The directory that is the common root of all the subtrees to be dumped must be specified as the last argument. The subtrees are specified by path names relative to this common root. The list of subtrees is provided from standard in. The list should have one item on each line, with a blank line to terminate the list.

If you use this option, you must also use option n.

n dumpname
Specifies the dumpname for a multi-subtree dump. Mandatory for multi-subtree dumps.

u: Update the file /etc/dumpdates after a successful dump. The format of /etc/dumpdates is readable by people. It consists of one free format record per line: subtree, increment level and ctime(3) format dump date. There can be only one entry per subtree at each level. The dump date is defined as the creation date of the snapshot being dumped. The file /etc/dumpdates may be edited to change any of the fields, if necessary. See dumpdates for details.

v: Verbose mode. The dump command prints out detailed information during the dump.

R: Restarts a dump that failed. If a dump fails in the middle and certain criteria are met, it becomes restartable. A restarted dump continues the dump from the beginning of the tapefile on which it previously failed. The tree argument should match the one in the failed dump. Alternatively, use ID, which is provided in the backup status command output, in place of the tree argument.

When restarting a dump, only the f option is allowed. All other options are inherited from the original dump.

All restartable dumps are listed by the backup status command.

EXAMPLES

To make a level 0 dump of the entire file system of volume “vol0” to a remote tape device with each tape file in the dump being less than 2 GB in size, use:

toaster> dump 0ufbB adminhost:/dev/rst0 63 2097151 /vol/vol0

To make a level 0 dump of the /home directory on volume “users” on a 2 GB tape to a remote tape device, use:

toaster> dump 0ufbB adminhost:/dev/rst0 63 2097151 /vol/users/home

To make a level 0 dump of the /home directory on volume “web” on a 2 GB tape to a local tape drive (no rewind device, unit zero, highest density) use:

toaster> dump 0ufbB nrst0a 63 2097151 /vol/web/home

To make a level 0 dump of the entire file system of the root volume to a local tape drive (no rewind device, unit zero, highest density), with each tape file in the dump being less than 2 GB in size, without operator intervention, using a tape stacker, with four tape files written per tape, assuming that the dump requires no more than 10GB, use:

toaster> dump 0ufbB nrst0a, nrst0a, nrst0a, urst0a, rst0a 63 2097151 /

This will:

Write the first three files to the norewind device, so that they, and the next dump done after them, will appear consecutively on the tape.

Write the next file to the unload/reload device. This will cause the stacker to rewind and unload the tape after the file has been written and then load the next tape.

Write the last file to the rewind device, so that the tape will be rewound after the dump is complete.

To back up all files and directories in a volume named engineering that are not in a qtree you created, use:

toaster> dump 0ufQ rst0a /vol/engineering

To run the dump command through rsh, enter the following command on a trusted host:

adminhost# rsh toaster dump 0ufbB adminhost:/dev/rst0 63 2097151 /home

To restart a dump on /vol/vol0/home, use:

toaster> dump Rf rst0a, rst1a, rst2a /vol/vol0/home

CLUSTER CONSIDERATIONS

In takeover mode, the failed filer does not have access to its tape devices. You can, however, back up the failed filer by entering the dump command in partner mode on the live filer. The dump command writes the data to the tape devices on the live filer.

FILES

/etc/dumpdates: dump date record

BUGS

Deleting or renaming a snapshot that is currently being backed up is not supported and will lead to dump errors.

NOTES

Restore
As stated previously, filer dump output format is compatible with Solaris ufsrestore. The filer supports a local restore command (see restore ), so the restoration process can be performed on the filer. It can also be be performed via a ufsrestore done on an NFS client machine; if such a restore is being done, the client system should be checked to ensure it supports SunOS-compatible dump/ restore format.

Client Dump and Restore Capability
If a client is to be used for performing filer dump and/or restore, it is important to check what the maximum dump and restore capabilities of your client system are before setting up a dump schedule. There are some client systems which do not support dump and restore of greater than 2 GB while others may support very large dumps and restores. It is especially important to check the restore capability of your system when using the filer local tape dump since the filer supports dumps that are greater than 2 GB.

Tape Capacity and Dump Scheduling
Along with the potential 2-GB restriction of dump or restore on a client system, it is important to consider your tape capacity when planning a dump schedule. For the filer local tape option, the Exabyte 8505 supports an approximate maximum capacity of 10GB per tape using compression. If a client system is used as the target for your dump, the capacity of that tape drive should be checked for dump planning.

If your filer file system exceeds the capacity of the local tape drive or the client system dump/restore, or you choose to dump multiple file system trees to parallelize the restore process with multiple tape drives, you must segment your dump to meet these restrictions.

One way to plan a dump schedule with a UNIX client system is to go to the root mount point of your filer and use the du command to obtain sizes of underlying subtrees on your filer file system. Depending on the restrictions of your client’s dump and restore capability or recording capacity of the tape device being used, you should specify a dump schedule that fits these restrictions. If you choose to segment your dump, the norewind device (see tape ) can be used to dump multiple tape files to one physical tape (again, choose a dump size which meets the criteria of your client restore and capacity of your tape drive).

The following example shows the du output from a filer file system on a client that supports dump and restore that are greater than 2 GB:

   client% du -s *   4108    etc   21608   finance   5510100 home   3018520 marketing   6247100 news   3018328 users

You can use a tape device with approximately 10 GB on each tape to back up this filer. The dump schedule for this system can use the norewind tape device to dump the mar_keting and news subtrees to one tape volume, then load another tape and use the norewind tape device to dump etc, finance, home and users subtrees to that tape volume.

CIFS Data
The Data ONTAP dump command dumps the CIFS attributes and 8.3 name data for each file that is backed up. This data will not be backed up by a dump run on an NFS client machine. This data will not be restored by a restore run on an NFS client machine. This data will only be restored if a local restore is done of a backup created by the Data ONTAP dump command.

Table of Contents