NAME
ufsdump - incremental file system dump
SYNOPSIS
/usr/sbin/ufsdump [options] [arguments] files_to_dump
DESCRIPTION
ufsdump backs up all files specified by files_to_dump (nor-
mally either a whole file system or files within a file sys-
tem changed after a certain date) to magnetic tape,
diskette, or disk file. When running ufsdump, the file sys-
tem must be inactive; otherwise, the output of ufsdump may
be inconsistent and restoring files correctly may be impos-
sible. A file system is inactive when it is unmouned or the
system is in single user mode. A file system is not con-
sidered inactive if one tree of the file system is quiescent
while another tree has files or directories being modified.
options is a single string of one-letter ufsdump options.
arguments may be multiple strings whose association with the
options is determined by order. That is, the first argument
goes with the first option that takes an argument; the
second argument goes with the second option that takes an
argument, and so on.
files_to_dump is required and must be the last argument on
the command line. It specifies the files to dump. Usually
it identifies a whole file system by its raw device name
(for example, /dev/rdsk/c0t3d0s6). Incremental dumps (lev-
els 1 to 9) of files changed after a certain date only apply
to a whole file system. Alternatively, files_to_dump can
identify individual files or directories. All files or
directories are dumped, which is equivalent to a level 0
dump; however, /etc/dumpdates is not updated, even with the
u option specified. In all cases, the files must be con-
tained in the same file system, and the file system must be
local to the system where ufsdump is being run.
If no options are given, the default is 9uf /dev/rmt/0
files_to_dump.
With most devices ufsdump can automatically detect the end-
of-media. Consequently, the d, s, and t options are not
necessary for multi-volume dumps, unless ufsdump does not
understand the way the device detects the end-of-media, or
the files are to be restored on a system with an older ver-
sion of the restore command.
OPTIONS
0-9 The dump level. All files specified by files_to_dump
that have been modified since the last ufsdump at a
lower dump level are copied to the dump_file destina-
tion (normally a magnetic tape device). For instance,
if a level 2 dump was done on Monday, followed by a
level 4 dump on Tuesday, a subsequent level 3 dump on
Wednesday would contain all files modified or added
since the level 2 (Monday) backup. A level 0 dump
copies the entire file system to the dump_file.
a archive_file
Archive file. Archive a dump table-of-contents in the
specified archive_file to be used by ufsrestore(1M) to
determine whether a file is in the dump file that is
being restored.
b factor
Blocking factor. Specify the blocking factor for tape
writes. The default is 20 blocks per write for tapes
of density less than 6250BPI (bytes-per-inch). The
default blocking factor for tapes of density 6250BPI
and greater is 64. The default blocking factor for
cartridge tapes (c option) is 126. The highest block-
ing factor available with most tape drives is 126.
Note: the blocking factor is specified in terms of
512-byte blocks, for compatibility with tar(1).
c Cartridge. Set the defaults for cartridge instead of
the standard half-inch reel. This sets the density to
1000BPI and the blocking factor to 126. Since ufsdump
can automatically detect the end-of-media, only the
blocking parameter normally has an effect. This option
can also be used for 8mm tape. However, since the size
(length) and density of 8mm tape differs from 1/4-inch
cartridge, if ufsdump has difficulty detecting the
end-of-media on a 8mm drive, these parameters should be
specified (with the s and d options) directly. This
option is incompatible with the d option, unless you
specify a density of 1000BPI with that option. When
cartridge tapes are used, and this option is not speci-
fied, ufsdump will slightly miscompute the size of the
tape. If the b, d, s or t options are specified with
this option, their values will override the defaults
set by this option.
d bpi
Tape density. Not normally required, as ufsdump can
detect end-of-media. This parameter can be used to
keep a running tab on the amount of tape used per reel.
The default density is 6250BPI except when the c option
is used for cartridge tape, in which case it is assumed
to be 1000BPI per track. Typical values for tape dev-
ices are:
1/2" tape 6250 BPI
1/4" cartridge 1000 BPI
2.3-Gbyte 8mm tape 54,000 BPI
5.0-Gbyte 8mm tape 54,000 BPI
The tape densities and other options are documented in
the st(7) man page.
D Diskette. Dump to diskette.
f dump_file
Dump file. Use dump_file as the file to dump to,
instead of /dev/rmt/0. If dump_file is specified as -,
dump to standard output.
If the name of the file is of the form machine::device,
the dump is done from the specified machine over the
network using rmt(1M). Since ufsdump is normally run
by root, the name of the local machine must appear in
the /.rhosts file of the remote machine. If the file
is specified as user@@machine::device, ufsdump will
attempt to execute as the specified user on the remote
machine. The specified user must have a .rhosts file
on the remote machine that allows the user invoking the
command from the local machine to access the remote
machine.
l Autoload. When the end-of-tape is reached before the
dump is complete, take the drive offline and wait up to
two minutes for the tape drive to be ready again. This
gives autoloading (stackloader) tape drives a chance to
load a new tape. If the drive is ready within two
minutes, continue. If it is not, prompt for another
tape and wait.
n Notify all operators in the sys group that ufsdump
requires attention by sending messages to their termi-
nals, in a manner similar to that used by the wall(1M)
command. Otherwise, such messages are sent only to the
terminals (such as the console) on which the user run-
ning ufsdump is logged in.
o Offline. Take the drive offline when the dump is com-
plete or the end-of-media is reached and rewind the
tape, or eject the diskette. In the case of some auto-
loading 8mm drives, the tape is removed from the drive
automatically. This prevents another process which
rushes in to use the drive, from inadvertently
overwriting the media.
s size
Specify the size of the volume being dumped to. Not
normally required, as ufsdump can detect end-of-media.
When the specified size is reached, ufsdump waits for
you to change the volume. ufsdump interprets the
specified size as the length in feet for tapes and car-
tridges, and as the number of 1024-byte blocks for
diskettes. The values should be a little smaller than
the actual physical size of the media (for example, 425
for a 450-foot cartridge). Typical values for tape
devices depend on the c option, for cartridge devices,
and the D option for diskettes:
1/2" tape 2300 feet
60-Mbyte 1/4" cartridge 425 feet
150-Mbyte 1/4" cartridge 700 feet
2.3-Gbyte 8mm 6000 feet
5.0-Gbyte 8mm 13000 feet
diskette 1422 blocks (Corresponds
to a 1.44-Mbyte diskette,
with one cylinder
reserved for bad block
information.)
S Size estimate. Determine the amount of space that is
needed to perform the dump without actually doing it,
and display the estimated number of bytes it will take.
This is useful with incremental dumps to determine how
many volumes of media will be needed.
t tracks
Specify the number of tracks for a cartridge tape. Not
normally required, as ufsdump can detect end-of-media.
The default is 9 tracks. The t option is not compati-
ble with the D option. Values for Sun-supported tape
devices are:
60-Mbyte 1/4" cartridge 9 tracks
150-Mbyte 1/4" cartridge 18 tracks
u Update the dump record. Add an entry to the file
/etc/dumpdates, for each file system successfully
dumped that includes the file system name, date, and
dump level.
v Verify. After each tape or diskette is written, verify
the contents of the media against the source file sys-
tem. If any discrepancies occur, prompt for new media,
then repeat the dump/verification process. The file
system must be unmounted. This option cannot be used
to verify a dump to standard output.
w Warning. List the file systems that have not been
backed up within a day. This information is gleaned
from the files /etc/dumpdates and /etc/vfstab. When
the w option is used, all other options are ignored.
After reporting, ufsdump exits immediately.
W Warning with highlight. Similar to the w option, except
that the W option includes all file systems that appear
in /etc/dumpdates, along with information about their
most recent dump dates and levels. File systems that
have not been backed up within a day are highlighted.
EXAMPLES
To make a full dump of a root file system on c0t3d0, on a
150-MByte cartridge tape unit 0, use:
example# ufsdump 0cfu /dev/rmt/0 /dev/rdsk/c0t3d0s0
To make and verify an incremental dump at level 5 of the usr
partition of c0t3d0, on a 1/2" reel tape unit 1, use:
example# ufsdump 5fuv /dev/rmt/1 /dev/rdsk/c0t3d0s6
FILES
/dev/rmt/0 default unit to dump to
/etc/dumpdates dump date record
/etc/group to find group sys
/etc/hosts to gain access to remote system with
drive
/etc/vfstab list of file systems
SEE ALSO
cpio(1), tar(1), dd(1M), devnm(1M), prtvtoc(1M), rmt(1M),
shutdown(1M), ufsrestore(1M), volcopy(1M), wall(1M),
wall(1M) st(7)
DIAGNOSTICS
While running, ufsdump emits many verbose messages. exit
codes:
0 Normal exit.
1 Startup errors encountered.
3 Abort - no checkpoint attempted.
NOTES
Read Errors
Fewer than 32 read errors on the file system are ignored.
Process Per Reel
Because each reel requires a new process, parent processes
for reels that are already written hang around until the
entire tape is written.
Operator Intervention
ufsdump requires operator intervention on these conditions:
end of volume, end of dump, volume write error, volume open
error or disk read error (if there are more than a threshold
of 32). In addition to alerting all operators implied by
the n option, ufsdump interacts with the operator on
ufsdump's control terminal at times when ufsdump can no
longer proceed, or if something is grossly wrong. All ques-
tions ufsdump poses must be answered by typing yes or no, as
appropriate.
Since backing up a disk can involve a lot of time and
effort, ufsdump checkpoints at the start of each volume. If
writing that volume fails for some reason, ufsdump will,
with operator permission, restart itself from the checkpoint
after a defective volume has been replaced.
Suggested Dump Schedule
It is vital to perform full, "level 0", dumps at regular
intervals. When performing a full dump, bring the machine
down to single-user mode using shutdown(1M). While prepar-
ing for a full dump, it is a good idea to clean the tape
drive and heads. Incremental dumps should be performed with
the system running in single-user mode.
Incremental dumps allow for convenient backup and recovery
of active files on a more frequent basis, with a minimum of
media and time. However, there are some tradeoffs. First,
the interval between backups should be kept to a minimum
(once a day at least). To guard against data loss as a
result of a media failure (a rare, but possible occurrence),
capture active files on (at least) two sets of dump volumes.
Another consideration is the desire to keep unnecessary
duplication of files to a minimum to save both operator time
and media storage. A third consideration is the ease with
which a particular backed-up version of a file can be
located and restored. The following four-week schedule
offers a reasonable tradeoff between these goals.
Sun Mon Tue Wed Thu Fri
Week 1: Full 5 5 5 5 3
Week 2: 5 5 5 5 3
Week 3: 5 5 5 5 3
Week 4: 5 5 5 5 3
Although the Tuesday through Friday incrementals contain
"extra copies" of files from Monday, this scheme assures
that any file modified during the week can be recovered from
the previous day's incremental dump.
Process Priority of ufsdump
ufsdump uses multiple processes to allow it to read from the
disk and write to the media concurrently. Due to the way it
synchronizes between these processes, any attempt to run
dump with a nice (process priority) of `-5' or better will
likely make ufsdump run slower instead of faster.
Overlapping Partitions
Most disks contain one or more overlapping slices because
slice 2 covers the entire disk. The other slices are of
various sizes and usually do not overlap. For example, a
common configuration places root on slice 0, swap on slice
1, /opt on slice 5 and /usr on slice 6.
It should be emphasized that ufsdump dumps one ufs file sys-
tem at a time. Given the above scenario where slice 0 and
slice 2 have the same starting offset, executing ufsdump on
slice 2 with the intent of dumping the entire disk would
instead dump only the root file system on slice 0. To dump
the entire disk, the user must dump the file systems on each
slice separately.
BUGS
The /etc/vfstab file does not allow the desired frequency of
backup for file systems to be specified (as /etc/fstab did).
Consequently, the w and W options assume file systems should
be backed up daily, which limits the usefulness of these
options.