 |
Index for
Section 8 |
|
 |
Alphabetical
listing for V |
|
 |
Bottom of
page |
|
vdump(8)
NAME
vdump, rvdump - Performs full and incremental backups on filesets
SYNOPSIS
/sbin/vdump -h
/sbin/vdump -V
/sbin/vdump [-w]
/sbin/vdump [-0..9] [-CDNPUquv] [-F num_buffers] [-T tape_num] [-b size]
[-f device] [-x num_blocks] fileset
/sbin/rvdump -h
/sbin/rvdump -V
/sbin/rvdump -w
/sbin/rvdump [-0..9] [-CDNUquv] [-F num_buffers] [-T tape_num] [-b size]
[-f nodename:device] [-x num_blocks] fileset
OPTIONS
-b size
Specifies the number of 1024-byte blocks per record in the saveset. The
valid range is 2 through 64 blocks; the default is 60 blocks per
record. The value of this option also determines the size of the in-
memory buffers.
-C Compresses the data as it is backed up, which minimizes the saveset
size.
-D Performs a level 0 backup on the specified subdirectory. This option
overrides any backup level specification in the command. If this option
is specified, the AdvFS user and group quota files and the fileset
quotas are not backed up.
-f device
-f nodename:device
Specifies the destination of the saveset.
For vdump, the local destination can be a device, a file, or, when the
- (dash) character is specified, standard output.
For rvdump, the mandatory specification is nodename:device to specify
the remote machine name that holds the device or file.
-F num_buffers
Specifies the number of in-memory buffers to use. The valid range is 2
through 64 buffers; the default is 8 buffers. The size of the in-
memory buffers is determined by the value of the -b option.
-h Displays usage help for the command.
-N Does not rewind the storage device when it is a tape.
-P Produces backward-compatible savesets that can be read by earlier
versions of the vrestore command. However, some data, such as very
large quota limits, can be lost in such a saveset.
-q Displays only error messages; does not display information messages.
-T tape_num
Specifies the starting number for the first tape. The default number is
1. The tape number is used only to prompt the operator to load another
tape in the drive.
-u Updates the /etc/vdumpdates file with a timestamp entry from the
beginning of the backup.
-U Does not unload the storage device when it is a tape.
-v Displays the names of the files being backed up.
-V Displays the current version of the command.
-w Displays the filesets that have not been backed up within one week.
-x num_blocks
Specifies an "exclusive or" (XOR) operation each time the blocks
specified by num_blocks are written to the saveset. The XOR operation
is performed on the blocks and the results written to the saveset as an
XOR block that immediately follows the blocks. Subsequently, the
vrestore command can use this block to recover one of the blocks in the
group should a read error occur. The valid range is 1 through 32
blocks; the default is 8 blocks. Using the -x option creates larger
savesets and increases the amount of time required to back up a file
system, but offers additional protection from saveset errors.
-0..9
Specifies the backup level. The value 0 for this option causes the
entire fileset to be backed up to the storage device. The default
backup level is 9.
OPERANDS
fileset
Specifies the full path name of a mounted AdvFS fileset to be backed
up. Alternatively, specifies a mounted NFS or UFS file system. When
used with the -D option, specifies a subdirectory.
DESCRIPTION
The vdump command backs up files and any associated extended attributes
(including ACLs, see the proplist(4) and acl(4) reference pages) from a
single mounted fileset or clone fileset to a local storage device.
The rvdump command backs up files and any associated extended attributes
(including ACLs, see the proplist(4) and acl(4) reference pages) from a
single mounted fileset or clone fileset to a remote storage device.
The vdump and rvdump commands are the backup facility for the AdvFS file
system. However, the commands are file-system independent, and you can use
them to back up other file systems, such as UFS and NFS.
The commands back up all files in the specified fileset that are new or
changed since a certain date and produce a saveset on the storage device.
The date is determined by comparing the specified backup level to previous
backup levels recorded in the /etc/vdumpdates file. The default storage
device for the vdump command is /dev/tape/tape0_d1. You can specify an
alternate storage device by using the -f option. There is no default
storage device for the rvdump command; it must be specified.
The commands perform 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/vdumpdates file.
Note that an incremental dump only captures the files that have changed,
ignoring all others. This means that if you perform a level 0 dump and a
later incremental dump, deleted files are not marked as gone (deleted). If
you then do a complete restore with a level 0 saveset and incremental
backups, the deleted files will be restored. You must then delete these
files individually.
The commands back 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 commands initiate a level 0 backup. A level 0
backup backs up all the files in the fileset.
After the backup operation is complete, you can use the vrestore -t command
to verify that the backup contains the files you wanted to save. This
command lists the name and size of each file in the saveset without
restoring them.
When you specify the -C option, the commands back up the files with
compression. You cannot specify the compression ratio, it is determined by
the contents of the dump.
When you specify the -u option, the commands enter 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 commands append the file with a new vdump
record; otherwise, the commands overwrite the existing record, changing the
backup date to reflect the most current backup session. This occurs after
all files in the named fileset have been successfully backed up.
Archives that were created prior to Tru64 UNIX Version 5.0 will be restored
with the same characteristics they would have if they were restored on the
earlier systems. For example, any UFS sparse files archived with the vdump
command prior to Tru64 UNIX Version 5.0 will be allocated disk space and
filled with zeros and any AdvFS striped sparse files archived with the
vdump command prior to Version 4.0D will be allocated disk space and filled
with zeros.
You do not have to be the root user to use the vdump or the rvdump command.
The AdvFS quota files and fileset quotas in the fileset are included in a
saveset when you are the root user and a full fileset is saved. AdvFS
quota files and fileset quotas can only be backed up for locally-mounted
filesets.
Under normal usage, the commands use a small amount of additional space on
the storage device, typically less than 1 percent, when a fileset is backed
up. If the -x option is used, the amount of additional space used to back
up the fileset increases.
If you use either of the commands to back up a fileset to an output file
that is part of the fileset you are backing up, there are two results you
should be aware of:
· That output file could be twice the size it should be.
· When you restore that output file, you obtain only a partial copy of
it.
To inform you of the situation, the commands display a message similar to
the following:
vdump: /demo/vdump.file is on the same device as /demo, this
vdump: could cause recursive back up problems.
vdump: Do you want to abort the dump? (yes or no).
Typically, you would want to abort the backup operation and select another
file on which to back up the fileset. However, there may be situations
when you do not want to abort the operation. For example, if you are
backing up a portion of a fileset using the -D option, you can store the
resulting output file in the same fileset in a section not being backed up.
RESTRICTIONS
To run the rvdump command, you must be able to execute the rsh command on
the remote node to which you are dumping. See rsh(8) for server and client
access rules.
The vdump and rvdump commands do not back up filesets that are not mounted.
Filesets backed up by using the vdump or the rvdump command must be
restored by using the vrestore or the rvrestore command. The vdump and
rvdump commands are not interchangeable with the dump and rdump commands.
Similarly, the vrestore and the rvrestore commands are not interchangeable
with the restore and rrestore commands.
The vrestore command in DIGITAL UNIX versions earlier than Version 4.0
cannot be used to restore savesets produced by the vdump command in DIGITAL
UNIX Version 4.0 or higher systems or in Tru64 UNIX systems.
If the vdump and rvdump commands attempt to write to a disk partition that
contains a valid disk label, the device driver will not overwrite the disk
label. An error is returned by the driver for character devices but not for
block special devices, so you must take special care if you use block
special devices. Therefore, if you are dumping to a partition that contains
block 0 of a disk, you must first clear the disk label. If you do not, the
vrestore and rvrestore commands interpret the disk label as part of the
saveset, resulting in an error.
If your partition does not start at block 0, there is no problem because
the vdump and rvdump commands will not attempt to write over the disk
label.
The /etc/vdumpdates file is written in ASCII and consists of a single
record per line. You must be the root user to update this file or to
change any record field.
Caution
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
1. A typical /etc/vdumpdates file includes entries like the following,
defining the fileset name, last backup level, and date:
dmn2#set2 8 wed Apr 21 07:40:35 1999
dmn2#set2 9 Thu Apr 22 07:20:42 1999
dmn2#set2 3 Fri Apr 23 07:47:37 1999
dmn2#set2 7 Thu Apr 22 08:23:05 1999
/dev/disk/dsk0g 0 Mon Apr 26 12:11:42 1999
In this example, dmn2#set2 represents an AdvFS fileset;
/dev/disk/dsk0g represents a UFS 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/disk/dsk0g entry because it does
not match the specified fileset, dmn2#set2.
·
The vdump command ignores the level 8 and 9 entries because 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.
·
The vdump command modifies the access time of each file in the
fileset.
2. To perform a full level 0 backup of a local fileset to a local device,
enter a command similar to the following:
% vdump -0 -u -f /dev/tape/tape1_d6 /fs1
In this example, -0 specifies that all files in the fileset /fs1 will
be backed up to /dev/tape/tape1_d6; -u specifies vdump to update the
/etc/vdumpdates after a successful backup of the fileset.
3. To perform a full level 0 backup of a local fileset to a remote
device, enter a command similar to the following:
# rvdump -0 -u -f pease:/dev/tape/tape1_d6 /fs1
In this example, -0 specifies that all files in the fileset /fs1 will
be backed up to the remote device /dev/tape/tape1_d6 on machine node
pease; -u specifies rvdump to update the /etc/vdumpdates file after a
successful backup of the fileset.
4. When the backup saveset device is the character - (dash), the vdump
command writes to standard output. Thus, the vdump and vrestore
commands can be used in a pipeline expression to copy filesets. The
following are typical commands; they are equivalent:
# vdump -0 -f - /usr | (cd /mnt; vrestore -x -f -)
# vdump -0f - /usr | vrestore -xf - -D /mnt
The rvdump and rvrestore commands are unable to use the character -.
The output device must be specified.
5. When using the vdump and rvdump commands to dump to a disk partition
that contains a reference to block 0 of a block special device, you
must first clear the disk label. If you do not, the dump process may
appear successful, but the restore will not be:
# rvdump -f mantis:/dev/disk/dsk2a -D /qarun
path : /qarun
dev/fset : qarun#qarun
type : advfs
advfs id : 0x358847e8.00033989.1
rvdump: Date of last level 0 dump: the start of the epoch
rvdump: Dumping directories
rvdump: Dumping 30212891 bytes, 198 directories, 1881 files
rvdump: Dumping regular files
rvdump: Status at Wed Jul 15 18:17:05 1998
rvdump: Dumped 30212891 of 30212891 bytes; 100.0% completed
rvdump: Dumped 198 of 198 directories; 100.0% completed
rvdump: Dumped 1881 of 1881 files; 100.0% completed
rvdump: Dump completed at Wed Jul 15 18:17:05 1998
# rvrestore -xf mantis:/dev/disk/dsk2a -D /tmp
rvrestore: unable to use save-set; invalid or corrupt format
6. For weekly tape backups, a set of 5 tapes per backed up fileset can be
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:
______________________________
M Tu W Th F
______________________________
Weekly 0 3 2 5 4
Biweekly 0 3 2 5 4
0 9 8 9 9
Monthly 0 3 2 5 4
1 9 8 9 9
1 3 2 5 4
1 9 8 9 9
______________________________
FILES
/sbin/vdump
Specifies the vdump command path.
/sbin/rvdump
Specifies the rvdump command path.
/etc/vdumpdates
Contains a list of filesets that were backed up, the date that each
file system was backed up, and the backup level.
/etc/fstab
Contains the full path names and mount points of filesets.
SEE ALSO
Commands: mount(8), umount(8), rsh(8), vrestore(8), rvrestore(8)
Files: acl(4), proplist(4)
|
Index for
Section 8 |
|
|
Alphabetical
listing for V |
|
 |
Top of
page |
|