
		BACKD

What is Backd:

	Backd is a daemon, looking at backup directive and doing
	everything as an autonomous process, I try to have it as
	simple and forgiving as possible.

	The idea behind backd, is to just receive mail asking
	to insert a tape with a specific ID in the tape device, 
	backd will do the backup and advice sysadmin when the 
	scheduled backup is completed, requesting then the next
	tape for the next schedled backup (and so one....)

Critical components:

	All files are located from a base directory (usualy
	/var/lib/backd).

	conf/tapelist:
	In order to be useable, backd need to now about a
	set of tapeid, that list is stored in the file
	tapelist (a tapelist example is provided). 
	You need to prepare a set of tape and to "marke"
	those tapes, such backd can be sure it is writing
	the right media.
	To "marke" tapes, use the provided backd utility
	named "marker" (see "marker" manual).

	conf/tapedev:
	in order to now were to use the tape, you must
	have a relation between tape type and a device.
	that's the tapedev purpose. An example is
	provided in conf and it is (I believe) really
	straightfoward to undertand.

	backlist/*
	That were you put you backup directives (an example 
	is provided see conf.released/bckdlist.exp).
	Each directive include a backup frequency, media type,
	a to kept value, and a included/excluded set of file.
	If you have more than one backup which must be done
	at a specific time, all data to backup will be stored
	on the same media as backup segment.
	You can use "reader" to read a specific backup from the tape. 
	Information extracted need to feed an desarchiver 
	(usualy cpio -i) to do the actual recovery.
	You can have MORE THAN ONE backup file, each one with its
	own set of included/excluded directive and backup
	frequency. backd will merge all the informations to collect
	backup and put them on the same media.

	data/*
	That the backd working directory, can be looked at, but unwise
	to modified or to erase files in this area unless you know very
	well what you are doing.


Starting backd:
	
	Backd is a daemon which need to be started during
	the booting phase, once aware about available tape,
	backd should take care of backup all day long....

	If you are using RPM, the install process setup
	a S91backd in rc3.d and rc5.d. backd should restart
	automaticaly even if you reboot your system.


components:

	backd has 3 components, the daemon itselft called
	backd, a tape marker to write a marker on the
	tape itself, the reader to read a tape once
	done by backd. See the manual for the different
	program available option.

	Note: backd is using cpio to write a tape, such
	to recover a tape you just need to skip over
	the tape marker and feed cpio to recover file
	inside the tape (ex: dd if=/dev/tape skip=2 | cpio -i).


Copyright issues:

	backd is GPL, sources are available, suggestions, patchs, 
	comments are welcomed. Send E-mail to jmp@safe.ca
	
