NAME

fdump − incremental file system dump

SYNOPSIS

/etc/fdump key [ argument ... ] filesystem
/etc/fdump -key [ argument ] ...  filesystem
 

DESCRIPTION

Dump 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 characters from the set 0123456789fbusdWn.

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 “−”, fdump writes to standard output. 

b The next argument specifies the size of the buffer (in kilo-bytes) written to the output device.  The default is 10 (10240-byte records).  However, if the density specified is 6250bpi or greater, the default is 32 (32768-byte records).  Note that the specified blocksize should be no greater than the maximum block size permitted by the tape driver (currently 32). 

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, fdump 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. 

c The tape unit being dumped to is a cartridge tape. 

B The next argument specifies the length of the tape reel in 1024-byte blocks.  Use of this option overrides the c,s, and d options.  This option is used with special non-standard tapes such as 8mm Exabyte cartridges.  Values for a few common Exabyte-8200 tape sizes are as follows:

tapeB value
15m265000
54m1070000
112m2080000

W fdump 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 fdump 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 fdump exits immediately. 

w Is like W, but prints only those filesystems which need to be dumped. 

n Whenever fdump requires operator attention, notify by means similar to a wall(1M) all of the operators in the group “operator”. 

R The next argument is the name of a file describing the current tape number and current position of the tape in feet (or if the B option is set, in blocks).  On invocation, fdump reads this file to determine how many tapes have been processed by previous invocations of fdump.  On successful termination (be sure to check the exit status), fdump updates the file so it can be used by future fdump invocations.  This feature can be used in conjunction with a script (which you supply) to allow fdump to write multiple file system dumps on a single reel of tape. 
 
Before the first invocation of fdump, you should initialize the file to contain
 
1 0
 
indicating this is tape 1 and 0 feet of tape have been consumed. After each invocation of fdump, you should inspect the file to determine if a "reel change" has occurred (useful for writing labels for the tapes) and if there is perilously little tape left on the current reel for the next file system.  Note that when the B option is used, the second argument, which is blocks, will have a B appended to it.  If the B option was used on the first tape, it must be used on subsequent fdumps to the same tape. 

fdump 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, fdump interacts with the operator on fdumps control terminal at times when fdump can no longer proceed, or if something is grossly wrong.  All questions fdump poses must be answered by typing “yes” or “no”, appropriately. 

Since making a dump involves a lot of time and effort for full dumps, fdump checkpoints itself at the start of each tape volume.  If writing that volume fails for some reason, fdump 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. 

fdump 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 controlling fdump is busy, and will be for some time. 

Recommended Dump Procedure.  Start with a full level 0 dump

fdump 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:

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 is taken on a set of fresh tapes that is saved forever. 

FILES

/dev/rmt/0msdefault tape unit to dump to
/etc/dumpdatesformat dump date record
/etc/fstabdump table: file systems and frequency
/etc/groupto find group operator

SEE ALSO

restore(1M), dump(8), fstab(4)

DIAGNOSTICS

Many, and verbose. 

Fdump 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. 

BUGS

Sizes are based on 1600 BPI tape; the raw magtape device has to be used to approach these densities. 
 
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.

fdump with the W or w options does not report filesystems that have never been recorded in /etc/dumpdates, even if listed in /etc/fstab. 

CX/UX Administrator’s Reference