System Administration Commands ufsdump(1M)
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 (usu-
ally either a whole file system or files within a file sytem
changed after a certain date) to magnetic tape, diskette, or
disk file.
The ufsdump command can only be used on unmounted file sys-
tems, or those mounted read-only. Attempting to dump a
mounted, read-write file system might result in a system
disruption or the inability to restore files from the dump.
Consider using the fssnap(1M) command to create a file sys-
tem snapshot if you need a point-in-time image of a file
system that is mounted.
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. See OPERANDS for more information.
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
The following options are supported:
0-9 The "dump level." All files speci-
fied by files_to_dump that have been
modified since the last ufsdump at a
lower dump level are copied to the
dump_file destination (normally a
magnetic tape device). For instance,
if a "level 2" dump was done on Mon-
day, 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 block-
ing factor for tape writes. The
default is 20 blocks per write for
tapes of density less than 6250BPI
(bytes-per-inch). The default block-
ing factor for tapes of density
6250BPI and greater is 64. The
default blocking factor for car-
tridge tapes (c option) is 126. The
highest blocking factor available
with most tape drives is 126. Note:
the blocking factor is specified in
terms of 512-byte blocks, for compa-
tibility with tar(1).
c Cartridge. Set the defaults for car-
tridge instead of the standard
half-inch reel. This sets the den-
sity 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. When car-
tridge tapes are used, and this
option is not specified, 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 inch tape
6250 BPI
1/4 inch cartridge
1000 BPI The tape densities and
other options are documented in
the st(7D) 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 invok-
ing 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 autoload-
ing (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.
L string Sets the tape label to string,
instead of the default none. string
may be no more than sixteen charac-
ters long. If it is longer, it is
truncated and a warning printed; the
dump will still be done. The tape
label is specific to the ufsdump
tape format, and bears no resem-
blance to IBM or ANSI-standard tape
labels.
n Notify all operators in the sys
group that ufsdump requires atten-
tion by sending messages to their
terminals, 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 running
ufsdump is logged in.
N device_name Use device_name when recording
information in /etc/dumpdates (see
the u option) and when comparing
against information in
/etc/dumpdates for incremental
dumps. The device_name provided can
contain no white space as defined in
scanf(3C) and is case-sensitive.
o Offline. Take the drive offline when
the dump is complete or the end-of-
media is reached and rewind the
tape, or eject the diskette. In the
case of some autoloading 8mm drives,
the tape is removed from the drive
automatically. This prevents another
process which rushes in to use the
drive, from inadvertently overwrit-
ing 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 cartridges, and as the
number of 1024-byte blocks for
diskettes. The values should be a
little smaller than the actual phy-
sical size of the media (for exam-
ple, 425 for a 450-foot cartridge).
Typical values for tape devices
depend on the c option, for car-
tridge devices, and the D option for
diskettes:
1/2 inch tape
2300 feet
60-Mbyte 1/4 inch cartridge
425 feet
150-Mbyte 1/4 inch cartridge
700 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 inch cartridge 9
tracks
150-Mbyte 1/4 inch cartridge 18
tracks
T time_wait[hms] Sets the amount of time to wait for
an autoload command to complete.
This option is ignored unless the l
option has also been specified. The
default time period to wait is two
minutes. Specify time units with a
trailing h ( for hours), m (for
minutes), or s (for seconds). The
default unit is minutes.
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 (or
device_name as specified with the N
option), date, and dump level.
v Verify. After each tape or diskette
is written, verify the contents of
the media against the source file
system. 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.
OPERANDS
The following operand is supported:
files_to_dump 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 named
directories that may be examined by the user
running ufsdump, as well as any explicitly-
named files, are dumped. This dump is
equivalent to a level 0 dump of the indi-
cated portions of the filesystem, except
that /etc/dumpdates is not updated even if
the -u option has been specified. In all
cases, the files must be contained in the
same file system, and the file system must
be local to the system where ufsdump is
being run.
files_to_dump is required and must be the
last argument on the command line.
If no options are given, the default is 9uf /dev/rmt/0
files_to_dump.
USAGE
See largefile(5) for the description of the behavior of ufs-
dump when encountering files greater than or equal to 2
Gbyte ( 2**31 bytes).
EXAMPLES
Example 1: Using ufsdump
The following command makes a full dump of a root file sys-
tem on c0t3d0, on a 150-MByte cartridge tape unit 0:
example# ufsdump 0cfu /dev/rmt/0 /dev/rdsk/c0t3d0s0
The following command makes and verifies an incremental dump
at level 5 of the usr partition of c0t3d0, on a 1/2 inch
reel tape unit 1,:
example# ufsdump 5fuv /dev/rmt/1 /dev/rdsk/c0t3d0s6
EXIT STATUS
While running, ufsdump emits many verbose messages. ufsdump
returns the following exit values:
0 Normal exit.
1 Startup errors encountered.
3 Abort - no checkpoint attempted.
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
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
cpio(1), tar(1), dd(1M), devnm(1M), fssnap(1M), prtvtoc(1M),
rmt(1M), shutdown(1M), ufsrestore(1M), volcopy(1M),
wall(1M), scanf(3C), attributes(5), largefile(5), st(7D)
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 questions
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.
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