DUMP.FFS(1M-SysV) RISC/os Reference Manual DUMP.FFS(1M-SysV)
NAME
dump.ffs - incremental file system dump
SYNOPSIS
/etc/dump.ffs [ key [ argument ... ] filesystem ]
DESCRIPTION
dump.ffs copies to magnetic tape all files changed after a
certain date in the filesystem. The key specifies the date
and other options about the dump. key consists of charac-
ters from the set 0123456789fiusdWnb.
0-9 This number is the "dump level." All files modified
since the last date stored in the file /etc/dumpdates
for the same filesystem at lesser levels will be
dumped. If no date is determined by the level, the
beginning of time is assumed; thus the option 0
causes the entire filesystem to be dumped.
f Place the dump on the next argument file instead of
the tape. If the name of the file is ``-'', dump.ffs
writes to standard output.
u If the dump completes successfully, write the date of
the beginning of the dump on file /etc/dumpdates.
This file records a separate date for each filesystem
and each dump level. The format of /etc/dumpdates is
readable by people, consisting of one free format
record per line: filesystem name, increment level
and ctime(3C) format dump date. /etc/dumpdates may be
edited to change any of the fields, if necessary.
s The size of the dump tape is specified in feet. The
number of feet is taken from the next argument. When
the specified size is reached, dump.ffs will wait for
reels to be changed. The default tape size is 2300
feet.
d The density of the tape, expressed in BPI, is taken
from the next argument. This is used in calculating
the amount of tape used per reel. The default is
1600.
W dump.ffs tells the operator what file systems need to
be dumped. This information is gleaned from the
files /etc/dumpdates and /etc/fstab. The W option
causes dump.ffs to print out, for each file system in
/etc/dumpdates the most recent dump date and level,
and highlights those file systems that should be
dumped. If the W option is set, all other options
are ignored, and dump.ffs exits immediately.
Printed 1/15/91 Page 1
DUMP.FFS(1M-SysV) RISC/os Reference Manual DUMP.FFS(1M-SysV)
w Is like W, but prints only those filesystems which
need to be dumped.
i Exit after displaying the number of blocks that
should be dumped.
n Whenever dump.ffs requires operator attention, notify
by means similar to a wall(1) all of the operators in
the group "operator".
b The number of dump records per tape block is taken
from the next argument. By default, low density
(less than 6250 bpi) uses 10 records per block and
high density uses 32.
If no arguments are given, the key is assumed to be 9u and a
default file system is dumped to the default tape.
dump.ffs requires operator intervention on these conditions:
end of tape, end of dump, tape write error, tape 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
key, dump.ffs interacts with the operator on dump.ffs' con-
trol terminal at times when dump.ffs can no longer proceed,
or if something is grossly wrong. All questions dump.ffs
poses must be answered by typing "yes" or "no", appropri-
ately.
Since making a dump involves a lot of time and effort for
full dumps, dump.ffs checkpoints itself at the start of each
tape volume. If writing that volume fails for some reason,
dump.ffs will, with operator permission, restart itself from
the checkpoint after the old tape has been rewound and
removed, and a new tape has been mounted.
dump.ffs tells the operator what is going on at periodic
intervals, including usually 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 control-
ling dump.ffs is busy, and will be for some time.
Now a short suggestion on how to perform dumps. Start with
a full level 0 dump
dump.ffs 0un
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:
Page 2 Printed 1/15/91
DUMP.FFS(1M-SysV) RISC/os Reference Manual DUMP.FFS(1M-SysV)
3 2 5 4 7 6 9 8 9 9 ...
For the daily dumps, a set of 10 tapes per dumped file sys-
tem 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
is taken on a set of fresh tapes that is saved forever.
For QIC-24 (Quarter-inch cartridge) tapes, specify a density
of 800 and use the default length. For QIC-120 tapes,
specify a density of 23000 and length of 570.
When dumping to an Exabyte tape drive, a density of 54000
BPI should be specified. Also specify the length of the
tape, which is dependent on the cartridge type. There are
two types of cartridges, P5 and P6; look at the cartridge to
determine the type you are using.
The following table shows cartridge lengths and lengths to
be used for the dump.ffs command:
Cartridge Type P6 length P5 length
Exabyte Other actual dump actual dump
256MB 15 min 48 750 69 1175
512MB 30 min 98 1500 128 2200
1024MB 60 min 176 3000 246 4250
1536MB 90 min 261 4500 366 6300
2048MB 120 min 346 6000 n/a
The device names for the Exabyte 8mm cartridge tape drive
are /dev/mt/hc0 (rewinds when operation completed) and
/dev/mt/hc4 (no rewind). On the M/2000, there are also
alternate device names: /dev/mt/hcxd4 (rewind) and
/dev/mt/hcxd4n (no rewind).
EXAMPLES
To do a level zero dump of a filesystem to a 2048MB P6 car-
tridge, use a command similar to the following:
dump 0ds 54000 6000 filesystem
The above example writes to the default tape device
/dev/rmt/ctape0. To do the same dump to one of the Exabyte
devices, use a command like this:
dump.ffs 0dsf 54000 6000 /dev/mt/hc0 filesystem
FILES
/dev/usr default filesystem to dump from
/dev/rmt/ctape0 default tape unit to dump to
/etc/dumpdates new format dump date record
/etc/fstab dump table: file systems and frequency
Printed 1/15/91 Page 3
DUMP.FFS(1M-SysV) RISC/os Reference Manual DUMP.FFS(1M-SysV)
/etc/group to find group operator
SEE ALSO
restore.ffs(1M)
fstab(4) in the Programmer's Reference Manual.
DIAGNOSTICS
Many, and verbose.
dump.ffs exits with zero status on success. Startup errors
are indicated with an exit code of 1; abnormal termination
is indicated with an exit code of 3.
ERRORS
Fewer than 32 read errors on the filesystem are ignored.
Each reel requires a new process, so parent processes for
reels already written just hang around until the entire tape
is written.
dump.ffs with the W or w options does not report filesystems
that have never been recorded in /etc/dumpdates, even if
listed in /etc/fstab.
It would be nice if dump.ffs knew about the dump sequence,
kept track of the tapes scribbled on, told the operator
which tape to mount when, and provided more assistance for
the operator running restore.
The final message "DUMP: Tape rewinding" is misleading if
the output device has been specified as a no rewind tape
device, e.g. /dev/rmt/ctape4. The tape is not rewound for
these devices.
Page 4 Printed 1/15/91