afserver - the server program of the afbackup package

afserver [ -b ] [ -L <locale> ] [ <configuration-file> ]

The server program. It must be started by the inetd-superdaemon. The configuration-file is read as /usr/server/lib/server.conf if not given explicitly.

-b

Turns off buffering mode. This reduces performance but seems to be necessary on some OSes

-L <locale>

Set the locale to the given string. Note, that this option might not be honoured due to insufficiencies of the gettext implementation on some systems

/usr/server/lib/server.conf

Server configuration file (See: afserver.conf(8))

/var/log/afbackup

The directory for logging the server actions

/var/lib/afbackup

Save internal state information of the server here

/var/lib/afbackup/status

This file is updated, whenever a notable server status change occurs. The file is always removed and created again as status changes occur often and they are not worth keeping. This file only serves the purpose to get an information about what is currently going on. While reading or writing the current throughput is reported here about every 5 seconds. Logging of errors or warnings goes to the configured logfile

/var/lib/afbackup/pref_client

This file is maintained to prevent colliding client accesses. The clients should have a chance to get the server always again, when querying several times within a certain interval. The previously served client and a timestamp is saved here to grant this client preferred service within a certain interval. Actually since version 3.3.5 this file is obsolete

/var/lib/afbackup/bytes_on_tape

The persistent counters of the server side. A maximum number of bytes per tape can be configured and the server must remember, how much he had written to all of the tapes. It makes no sense to count them all each time a cartridge is loaded. The format of each line is: <cartridge-number>: <number-of-bytes-on-tape> <number-of-files-on-tape> <tape-full-flag> <last-writing-timestamp>

/var/lib/afbackup/tapepos

The name of this file can be configured in the serverside configuration file, but i think, noone will ever change it. This file contains entries, that specify tape positions in different contexts. Lines starting with a number followed by a colon specify the writing position for the cartridge set specified by the leading number. Lines starting with a device name field indicate, what tape in which position is currently in that drive. Each pair of numbers specifying a position consists of a cartridge number and a file number

/var/lib/afbackup/precious_tapes

This file contains a line for each client, listing which cartridges the client needs for restoring everything it saved and it wants access to. All cartridges listed here are considered read-only, if they have no more space on tape to write to. If they have free space, new data is appended at the end of the last file on tape during write

/var/lib/afbackup/readonly_tapes

This file contains lists of cartridge numbers, that should not be written to anymore. This file can be edited or modified sending an appropriate server message (See: afclient, option -M). The format of this file is simply numbers, ranges or comma-separated numbers of cartridges. A range can be given as [<start-number>]-[<end-number>], e.g. 2-4, -2 or 8-. In the last example the number of cartridges configured in the server configuration file will be applied for the end of the list

/var/lib/afbackup/cartridge_order

The server must remind, what tape follows which other one, because their order no longer follows the number of the cartridge and the server no longer starts writing the first one after the last one is full. Tapes can be set read-only or marked crucial for restoring some client. So it may occur, that the server must skip one or more tapes to find a writable one. Also in full append mode it might happen, that it is not the first file on tape, who follows the last one on a full tape. In this file the order is saved, what file on which tape must be read, when a certain tape is exhausted. Behind the number of the cartridge in the first column and the arrow characters -> the following numbers name the tape and file to be read next. This file should be saved to some other location, because it is crucial for restore

/var/lib/afbackup/tape_uses

This file contains a list of cartridge numbers in the first column, followed by a colon : . The second column contains a number indicating, how often this tape has become full up to now. This number is supplied to the configured Tape-Full-Command , whenever a tape becomes full

/var/lib/afbackup/cartridge_locations

This file contains the database, where the cartridges currently can be found. The first column is the cartridge number, followed by a colon. A space follows and the rest of the line either contains three fields: the device name of the media changer, a word to specify the location class (drive, slot or loadport), and a number counting instances of location classes, e.g. /dev/rmt/stctl0 slot 6 If the rest of the line is not of this form, it is considered to be a freetext description

/var/lib/afbackup/ever_used_blocksizes

This file contains a list of all the tape blocksizes, that have ever been used on the the server. The list is used to quickly find the correct blocksize for reading, when the tape cannot be read with the configured one. If tapes are used, that come from another server and have a tape blocksize, that this server has never seen, the unknown blocksize should be added to this file manually, one per line

afclientconfig(8), xafclientconfig(8), full_backup(8), incr_backup(8), afverify(8), afrestore(8), xafrestore(8), update_indexes(8), copy_tape(8), afclient.conf(8), afserver(8), afmserver(8), afserver.conf(8), cartis(8), cartready(8), label_tape(8), tar(1)

afbackup was written by Albert Fluegel (af@muc.de). This manpage was extracted from the text docs by Christian Meder (meder@isr.uni-stuttgart.de).