[Gllug] Tape Backups to DDS Drive

[Simon Andrew Boggis]

> Darren Beale and other wrote re backups to DDS drive.
> 
> Just a small comment on tape backups:-
> 
> If you do use scripts to do tape backups, wehther front-ending a 'tar' a 'cpio'
> or a 'dd' to do the actual dirty work, I have personally found it useful to
> first 'label' the tapes to be used by 'echoing' a 'name' of some sort to each
> tape (eg copy1, copy2, etc) and then rigging the scripts to prompt for the
> tape being used.  The script can then read the tape 'label' and check the
> correct tape is being used before proceeding to do the backup.
> Also the script could add a date and time stamp to the 'label' indicating
> when the copy was made.
> 
> Such a system can enable you to identify the contents of a tape if any paper
> records go astray, and also prevent possibly using the same tape twice in a
> row and effectively destroying the last backup befopre the next one is complete!
> 

I avoid all this scripting by using amanda - it does the labelling, figures
out what level of dump to do on each disk (and each host - backs up multiple
hosts to a tape over your network) each night and keeps records for you.

As to hardware, I sucessfully use amanda (with the scsi changer kernel module
from Gerd Knor) with an HP Surestore 35/70 Gb DLT 8 tape changer, an
HP Galactica 40/80 Gb DLT 20 tape changer and a pair of elderly Quantum
20/40 Gb DLT 5 tape changers. Having changers avoids needing a member of 
staff to change a tape every single day (or forget!) - amanda sends email 
when the tape library is finished. Amanda requires some work to set up
by someone with their head screwed on, but once done a monkey can change the
tapes with no problems (: On the down side, you can't yet span dumps across
tapes, and amanda can require more media than something handrolled as it 
always uses a whole tape whether you fill it or not per night.

Oh, scsi cards - my tape drives are connected to Ultra wide SCSI-II 
controllers - I have some old Adaptec AHA2940W controllers (you can't buy
them anymore as far as I know) but recently I've bought Advansys UW2 
controller which has explicit linux support from the manufacturer and works
just fine. I have got a scsi holding disk to buffer the dumps on one host,
but on the others I'm happily using large IDE hard disks (these are more
than fast enough for my network backups).

Simon

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Simon A. Boggis 					Systems Programmer
Department of Computer Science, 
Queen Mary and Westfield College London, E1 4NS, UK.    Tel. 020 7882 5234