dump2(1M) DG/UX R4.11MU05 dump2(1M)
NAME
dump2 - incremental file system backup
SYNOPSIS
/usr/sbin/dump2 [ options ] file-system
DESCRIPTION
Dump2 creates a data file of all files changed after a certain date
in a particular file system. file-system is the pathname of a
special file referring to a device containing a file system. Note
that file-system must refer to a local dg/ux file system (not a file
system mounted from another host).
File system dumps created with dump2 can be read by restore(1M).
Options
-Z (Pertains only to a system with DG/UX information security.)
Dump a standard dump format archive which can be restored on a
generic system. By default, dump2 creates a Trusted DG/UX®
format dump archive; each file's security attributes are
archived along with the file's standard attributes and
contents. A trusted DG/UX format dump archive can only be
read by trusted restore(1M) on a system with DG/UX information
security.
-dump-level
Indicate the dump level (0 through 9). All files modified
since the last date stored in the file /etc/dumpdates for the
same file system at lesser levels will be dumped. If no date
is determined by the level, the beginning of Jan. 1, 1970,
GMT, is assumed; thus the dump-level 0 dumps the entire file
system. The default is 9.
-B number-of-buffers
Specify number-of-buffers as the number of shared memory
buffers to use. A somewhat larger number may increase the
speed of dumps; however, research has shown that after a
relatively small number of buffers, adding additional buffers
provides no net increase in performance. So increasing this
number much beyond the default will probably only waste
resources. The default is 3.
-b buffer-size
Specify buffer-size to be the number of 1024-byte blocks
written per record. For tape devices which require blocking
factors, this argument should match the optimal blocking
factor for the particular device in use. The default is 10;
the maximum is 64.
-D output-disk-file-name
Write the output to output-disk-file-name without any tape
headers or trailers. This output can be used as input for
another dump by specifying the -T option.
-E exclude-list-file
Read the file exclude-list-file for a list of inode numbers to
exclude from the dump. Each inode number must appear on a
separate line. Any characters after the inode number are
ignored. The exclude-list-file may be "-" to indicate that
standard input is to be read.
-f dump-device
Place the dump on dump-device. The default is /dev/rmt/0. If
you have DG TCP/IP (DG/UX), you can use this option to dump to
a remote device. For example,
dump2 -0 -f sys:/dev/rmt/0 /dev/rdsk/root
lets you dump the root filesystem to the tape device "0" on
system "sys." To do this, you must be logged in as root on
your own system, and your system must have an entry in the
remote host's /.rhosts file.
-I include-list-file
Read the file include-list-file for a list of inode numbers to
include in the dump. Each inode number must appear on a
separate line. Any characters after the inode number are
ignored. The include-list-file may be "-" to indicate that
standard input is to be read.
-i Ignore tape size estimates. This allows dump2 to write to the
physical end of tape, rather than stopping when the estimate
indicates that end of tape is near.
-L log-file-name
Specify log-file-name as the name of the log file in which to
record messages from dump2. If this option is used, all
messages normally written to standard error are also appended
to log-file-name. If this option is not used, messages are
written only to standard error.
-M medium-name
Specify medium-name as the type of medium being dumped to.
medium-name must be an entry in the tape table file (see the
-t option).
-n Notify an operator (as in wall(1M)) whenever a response is
required at the operator's console. /etc/group must contain
an entry for "operator".
-O operator-input-fifo
Read operator input (i.e. answers to queries) from a fifo-
special file. Normally, dump2 writes operator messages to
stderr and reads operator responses from /dev/tty. This
option causes operator input to be read from operator-input-
fifo instead. This is very useful when running dump2 from
cron(1M) since cron jobs have no controlling tty. For
example,
dump2 -0 -f /dev/rmt/0 -O /tmp/fifo /dev/rdsk/root 2>/dev/console
would send all output of dump2 to the console, but would
solicit operator responses from /tmp/fifo. Running this
command from a cron job would allow you to send dump2 output
to the console without having to take control of the console
for input. Operator queries from dump2 (such as requests for
the next tape) could be answered by echoing the strings "yes"
or "no" to /tmp/fifo.
-s Report performance statistics after completion of dump. The
performance report includes the total elapsed time subdivided
into: time spent in initialization, time spent actually
dumping data, time spent waiting on tapes to rewind (not
including rewind time for the final tape), and time spent
waiting on operator intervention. It also includes the total
amount of data dumped and the average data transfer rate for
the dump.
-T input-file-name
Read filesystem information from input-file-name. This file
must be in the form produced by running dump2 with the -D
option.
-t tape-table-file-name
Read medium information from tape-table-file-name. The
default is /etc/dumptab.
-u Write the date of the beginning of the dump on the file
/etc/dumpdates, if the dump completes successfully. This file
records a separate date for each file system and each dump
level. The /etc/dumpdates file consists of one free format
record per line: file system name, increment level, and ctime-
format dump date.
-W Tell the operator what file systems need to be dumped. This
information is gleaned from the files /etc/dumpdates and
/etc/fstab. Dump2 prints out the most recent dump date and
level for each file system in /etc/dumpdates, and marks those
file systems that should be dumped. All other options are
ignored, and dump2 exits immediately.
-w Do as -W does, but print only those file systems that need to
be dumped.
-z Print the inode numbers of dumped files on the standard
output.
dump2 and restore support symbolic links and control point
directories.
dump2 requires operator intervention on end of tape, end of dump,
tape write error, tape open error, or disk read error (if there are
more than 32 errors). In addition to alerting all operators (with
the -n option), dump2 interacts with the operator on the dump2
command's control terminal when dump2 can no longer proceed, or if
something is grossly wrong. All questions dump2 poses must be
answered by typing yes or no.
Because making a full dump involves a lot of time and effort, dump2
allows the dump to continue if a bad tape block is encountered. If
at any point dump2 fails to write to the tape, dump2 will prompt the
operator for a new tape, and continue the dump.
At periodic intervals, dump2 tells the operator what is going on,
usually including low estimates of the number of blocks to write, the
number of tapes it will take, the time to completion, and the time to
the tape change. The output is verbose, so that others know that the
terminal controlling dump2 is busy and will be for some time.
Inode Lists
dump2 generates a list of inodes which are to be backed up. This
list includes all inodes which have changed since the last lower-
level dump, and which appear in some include-list-file, and which do
not appear in any exclude-list-file. By default, the include-list-
file contains all inodes for the file system, and the exclude-list-
file contains no inodes.
The inode numbers needed for either the include-list-file or the
exclude-list-file can be generated from the -i option to the ls(1)
command, or from the st_ino field of the stat(5) structure.
Dump Cycles
To perform dumps, start with a full level 0 dump:
dump2 -0un /dev/rdsk/root
Next, dumps of active file systems are taken on a daily basis, using
a modified Tower of Hanoi algorithm, with this sequence of dump
levels:
3 2 5 4 7 6 9 8 9 9 ...
For the daily dumps, a set of 10 tapes per dumped file system is used
on a cyclical basis. Each week, a level 1 dump is taken, and the
daily Hanoi sequence repeats with 3. For weekly dumps, a set of 5
tapes per dumped file system is used, also on a cyclical basis. Each
month a level 0 dump, which is saved indefinitely, is taken on a set
of fresh tapes.
EXAMPLES
In order to perform a complete backup of the root file system, invoke
dump2 as follows:
dump2 -0 -f /dev/rmt/0 /dev/dsk/root
In order to archive all files in the "/home" file system belonging to
user "smith", use the following lines:
find /home -user smith -exec ls -id {} \; > /tmp/file.list
dump2 -I /tmp/file.list -0 -f /dev/rmt/0 /home
rm /tmp/file.list
FILES
/etc/dumpdates Previous dump dates for each file system
/etc/fstab Dump frequency for each file system
/etc/group Group entry for "operator"
/etc/dumptab Table specifying media characteristics
SEE ALSO
restore(1M), ctime(3C), dumptab(4), fstab(4), group(4),
appropriate_privilege(5).
cap_defaults(5).
NOTES
Dump2 uses the -B and -b options to request approximately number-of-
buffers * buffer-size * 1024 bytes of shared memory. If dump2 cannot
get this amount of shared memory, either or both of these arguments
should be decreased. Alternatively, the system can be reconfigured
to make more shared memory available.
On systems with DG/UX information security, in most cases, dump2 will
correctly save data from mounted filesystems; however, there are
pathological cases where it can save incorrect backup images when
dumping mounted, active filesystems. In order to absolutely
guarantee the integrity of a backup, filesystems should be unmounted
while being dumped.
You must have appropriate privilege to use dump2. For systems with
DG/UX information security, appropriate privilege is defined as
having one or more specific capabilities enabled in the effective
capability set of the user. See cap_defaults(5) for the default
capabilities for this command.
On systems without DG/UX information security, appropriate privilege
means that your process has an effective UID of root. See the
appropriate_privilege(5) man page for more information.
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