faq

一套客户/服务器模式的备份系统代码,跨平台,支持linux,AIX, IRIX, FreeBSD, Digital Unix (OSF1), Solaris and HP-UX.

Can backup file system whose size is bigger than a tape.    NO(2)   YES
> Why not ?

Backups file system to tape if bigger than spool, or to
spool, or no backup.                                        TAPE(3) N/A
> No spool area is maintained. To achieve good performance,
> ring buffers are created on client and server, client-/
> server-protocol tries to optimize throughput.

Can append to tape.                                         NO(4)   YES
> Normal append is supported since ever. As of version
> 3.2.6 full append mode is implemented, i.e. also, if
> an administrator has requested to write to another
> tape now, the current one will be appended to, if there
> is no space left on any available tape. Since 3.2.7
> there is also a variable append mode making the server
> append to any supplied tape having remaining space
> and not being in read-only state

Supports a tape verify option (just verifying the tape)     YES     NO
> Don't see the use of this.

Supports a data verify option (compare with fs).            NO(5)   YES
> (very pedantic)

Graphical, web or menu-based configuration.                 NO      GUI,CL
> CL means: command line program

Graphical, web, menu-based or command line restore.         CMD     GUI,CL

Can restore individual file automatically to most recent.   YES     YES

Can restore individual file to specified date.              ???     YES

Protects a client host from others reading its data.        NO      YES
> Client access can be restricted on cartridge set base

Supports disaster recovery.                                 NO      YES

mt and tar commands are easy to use to recover by hand,
with the printed weekly summary.                            YES     YES
> No weekly summary, minimum restore info posted to admin.
> Manual recover is possible, explained in FAQ

License.                                                    BSD     GPL

Can backup MS-WINDOWS data ?                                YES     via SMB-mount


Now for the items from an afbackup preferring user's view (> prefixing
the comments of an amanda user, >> prefixing my thoughts on the comment):

End User Restore                                            NO      YES
> Amanda doesn't support end user restore

Data safety (client/server authentication through a
challenge-response, secret key required, real client-
server system, only server can access tape devices)         NO      YES
> Amanda does NOT have it, which makes it a problem.
> There ARE extensions, for example for using Kerberos
> (export problems), or ssh (other class of problems).

Database backup support (by saving arbitrary dump
command output)                                             NO      YES
> No, Amanda requests it to be sent to a file, first.
>> So e.g. for an online database backup a huge
>> temporary disk space is required

Raw device contents backup                                  NO      YES

Using full tape capacity                                    NO      YES
> No, Amanda insists on changing tape everyday (which
> makes sense for tape's security reason, but doesn't make
> too much sense if you waste a lot of precious storage
> --- Amanda counter-balances this with its intelligent
> scheduling algorithm).

Multi-Stream (several clients backup to a server in
parallel) optional                                          YES?    YES
> Multiple clients can backup to the spool, and then to
> tape. There is no tape multiplexing or anything like
> this.

Several servers per client can be configured, selected
by availability and load, transparent during restore        NO      YES

Per file preprocessing (for safety, if the whole stream
is e.g. compressed and a single bit is wrong during restore
all the rest is lost)                                       NO      YES
> Amanda compresses the whole backup if requested.
>> (AF's comment: crazy in my opinion)

Secure remote start option (not requiring trusted
superuser remote access)                                    NO      YES
> Backups are always started centrally. You can decide at
> which time the *whole* thing starts.
>> (AF's comment: also possible with afbackup, in a
>>  secure fashion)

End user restore (already mentioned above) only of his
own files                                                   NO      YES, also GRAPHICAL

Server and client can easily change (e.g. move tape to
other machine or restore to different client)               Y/N     YES
> Amanda stores the indexes on the server, so the client
> can easily change. However, the server can only change
> provided you restore the indexes.

Duplicate tapes (make clones) (also automatically)          NO      YES
> Not supported (you can make copies, but they won't be
> considered as though).

Store in filesystems, maybe removable disks                 NO      YES
(may call it virtual cartridges)

Cartridges can be set to read-only mode                     ???     YES
> Probably no.

Maintain arbitrary cartridge sets (e.g. to switch daily,
weekly or for type or backup)                               YES     YES
> Yes. Amanda's scheduler is probably better than afbackup's.
>> (AF's comment: i didn't speak of the scheduler here,
>>  but of the option to combine tapes to sets with
>>  common properties, e.g. access restrictions)



1.2 Amanda issues

(1) Support for security is low (a this time mainly based on host name
    security, without encryption). Kerberos or ssh encryption are possible,
    but not easy to set up/well tested, and have some exportation or
    patent issues.

(2) Cannot backup a file system whose size is bigger than a tape, without
    splitting the fs with regexps.

(3) Backups bigger than the spool size are dumped to tape, which is slower
    and may cause tape trashing.

(4) Only if the tape is disabled, in that case the system dumps to spool,
    and then a flush can be done. But cannot really *append* to a tape.
    Authors say it's a feature: the tape is not used for more than one day,
    this guarantees medium integrity, and the scheduler makes this
    worthwhile.

(5) Verify option would have to be implemented.


1.2 afbackup issues

To be implemented in the next versions:

(1) Jukebox support (several tape devices sharing a set of tapes), coming
    not too soon, depends on the time and support i get for ongoing
    development by my employer and customers.


Not planned to be implemented:

- Maintaining a spool area on disk
- Distinguished scheduler for the backup system (crond is in place, so ...)


Q34: How to contribute to I18N/L10N ?

     Ask to get a pattern file for your language. It will be sent to you
     containing pairs of msgid and msgstr entries. For a first attempt
     the file afbackup.pot in the subdirectory ./po can be used, copied
     to X.po with X replaced as explained below. But then it might be,
     that someone else is already working on the translations for your
     language, so better ask first.
     You have to fill in the msgstr parts. If the msgstr part will be
     longer than one line, put an empty string behind msgstr and continue
     to write in the next lines. Example:

msgid "some long English stuff"
msgstr ""
"The multiline\n"
"equivalent in some\n"
"other language."

     There are already multiline sections in the msgid fields. Please try
     to keep the output clearly arranged.

     To test your translations, put your X.po file into the subdirectory
     ./po of the distribution. Change to it and type the following line
     (X replaced with your language setting of LANG):

      msgfmt -o X.mo X.po

     The X.mo file will be created.
     Now make a directory under the installation directory
     /.../common/share/locale (again X replaced):

      mkdir -p /.../common/share/locale/X/LC_MESSAGES

     now copy the X.mo file to that directory renaming it to afbackup.mo:

      cp X.mo /.../common/share/locale/X/LC_MESSAGES/afbackup.mo

     When you now set the environment variable LANG to the setting
     you use for other programs, afbackup should speak your language.
     Please send the X.po file with your add-ons to the author (please
     gzip -9 or bzip2 -9 before sending !!!)

     Thanks a lot !


Q35: Why does I18N not work in my environment ?

A35: A common problem is, that the programs are linked with a libintl.X,
     that does not understand the format of the .mo file. Either GNU
     msgfmt is used to create the .mo file and the vendor's lib is
     linked to your binary or the other way round. This may happen,
     though i tried to make autoconfig do it's best to find out, which
     program and which function is what sort of. To use the vendor's
     /usr/bin/msgfmt and /lib/libintl.XY, you can change to the po
     directory and run  msgfmt -o XY.mo XY.po with XY replaced with
     your language abbreviation, then  make install  again.

     If you get a warning during build, that no msgfmt program could
     be found, either add the path to GNU msgfmt to your command path
     and build again, or if no msgfmt can be found, install GNU gettext
     and start over. If GNU msgfmt is available on another architecture,
     you can simply copy the *.gmo files into the po directory and build
     again without the  make distclean  before.

     If all this does not help, the problems are elsewhere. It has been
     experienced, that afbackup I18N does not work on Solaris-2.6 while
     it does on Solaris-2.5.1 and Solaris-2.7. Strange, isn't it ?
     Any help concerning these topics is appreciated.


Q36: Is there a mailing list or a home page for afbackup ?

A36: Yes. The Homepage is http://www.sourceforge.net/projects/afbackup

     The alias http://www.afbackup.org is redirected to this URL and
     might go out of service silently.

     If you want to be informed about important changes or bugfixes,
     monitor the desired releases on the afbackup homepage.


Q37: I have trouble using the multi stream server. What can i do ?

A37: Trouble with the multi stream server are supposed to be related to
     the inetd, especially when using xinetd. In these cases the afmserver
     can be started as daemon not using (x)inetd. For this purpose there
     are the options -d and -p <port>. Please note, that this mode to run
     the afmserver requires a more tolerant and robust client behaviour
     first implemented in version 3.2.7. Older clients may have problems.

     The afmserver can e.g. be started at system boot time using the line
     below. As it should run usually under a different user ID than 0,
     which is root's, an su to this ID must be preceded (see column 5 of
     the single stream server's entry in /etc/inetd.conf for the name of
     the user). Then the line might look something like this:

      su backup -c "/usr/local/afbackup/server/bin/afmserver -d -p afmbackup /usr/local/afbackup/server/lib/backup.conf"

     The program goes into the background, so no & is required. The
     daemon can be killed normally, when not needed any more.

     A typical init-script might look like this (modify the setting of
     BASEDIR appropriately, check, if the configuration file is correct
     as $BASEDIR/lib/backup.conf and modify, if not):

#!/bin/sh
#
# I *love* RCS
#
# $Source: /home/alb/afbackup/afbackup-3.3.8.1/RCS/FAQ,v $
# $Id: FAQ,v 1.2 2005/01/15 08:59:36 alb Exp alb $
#

BASEDIR=/usr/local/afbackup/server

CONFIGFILE=$BASEDIR/lib/backup.conf

#
# cheap trick, might fail, then set PS accordingly
#
PS="ps -uxaww"
$PS >/dev/null 2>&1
if [ $? -ne 0 ] ; then
  PS="ps -ef"
fi

case "$1" i