Hi Jo, at the end is an addition I'd like to see added to section 3.6. Why does my XYZ backup program complain about "Invalid argument" errors?
of the ftape FAQ. Thank you! > I cannot get Tob to use the tape with afio. I even reinstalled tob after > removing all my old configuration files which I used when I did backups to > a second hard drive. The tob error message reads : > > afio: "/dev/fape": Invalid argument. Here's the corresponding section of the Ftape-FAQ (FAQ == frequently asked questions). Maybe the beta-5 and beta-6 versions of the FAQ doesn't contain this answer, below is included the section of the FAQ that Johan De Wit has put together (thanks, Jo!); it is available in html format from the ftape web page http://www-math.math.rwth-aachen.de/~LBFM/claus/ftape in the "Documentation" subsection of that docuement. It is planned that Jo places the html version of the FAQ on a web server he has direct access to; until this has been made possible recent versions of the FAQ are available from the Ftape Home Page as indicated above. You can either read the html version on-line, or download the sgml source from the web page. Post 3.04-beta-6 versions will contain the text version of the most recent FAQ at release time of the respective ftape version. ********************************************************************** Please read the Faq. Thank you! If your problem isn't dealt with in the FAQ then use the mailing list, if the answers given in the FAQ are not clear enough, then please try to improve the FAQ. If you can't correct the answers yourself, then please drop a short note to the FAQ maintainer: Johan De Wit <[EMAIL PROTECTED]> the Ftape maintainer: Claus-Justus Heine <[EMAIL PROTECTED]> the Linux tape mailing list: <linux-tape@vger.rutgers.edu> stating that you found an answer to your question in the FAQ, but couldn't understand what the hell people were talking about in that answer. If you feel that something is missing in the FAQ then please also notify us using all of the addresses given above. Other improvements (correction of typos etc.) are also welcome! Please include the word FAQ in the subject line if you are sending an email that is FAQ related, i.e. suggests improvements to the Ftape FAQ. Thank you. ********************************************************************** Here you go: ------------------------------------------------------------------------ 3.6. Why does my XYZ backup program complain about "Invalid argument" errors? zftape requires the data to be written in multiples of a fixed minimal block size. This is a very usual behavior for a tape device. There are three ways to get rid of those errors: o set Ftape's block size to the block size used by the backup program. The example below works for "afio": mt -f /dev/qft0 setblk 5120 o If you don't want to use Ftape's built in compression you can also use mt -f /dev/qft0 setblk 0 to switch Ftape to variable block size mode and be able to write the data in arbitrary portions to the tape (BUT: the builtin compression doesn't work with this setting). When you intend to use "KBackup" then this is the only way to make it work together with Ftape (it _may_ work, don't know if it does) o tell your backup program about Ftape's default block size of 10k (which is also the default of GNU tar). For "afio" you can use the following command line switch: afio -b 10k ... You may want to read the section "Tape blocks" of the manual (use its "Concept index" to directly jump to that section) <answer by Claus Heine> ------------------------------------------------------------------------ > "tar -czvf /dev/ftape *" does not work but > "tar -cvf /dev/ftape *" works. Well, this isn't stated very clearly in the FAQ. We should add the following to the answer given above. ######################################################################## When using GNU tar's builtin compression with GNU tar versions prior to tar-1.12 one needs to run tar with the "--block-compress" switch to "re-block" the output to the tape. Otherwise tar will compress the data it reads and write it in arbitrary portions to the tape. Example: tar -czvf /dev/qft0 --block-compress /etc WARNING: One shouldn't use tar's builtin compression with large backups as it makes the entire data stream one huge compressed block. If such archives are corrupted right at the beginning it will be very difficult to recover. ######################################################################## -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word "unsubscribe" to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED] .
