Carlos E. R. wrote: > > The Thursday 2007-04-26 at 13:52 +0100, G.T.Smith wrote: > > > Carlos E. R. wrote: > > >> As to backup to DVD, there is "dar" and "kdar". Plus "par", that I > still > >> haven't evaluated. > > kdar is the frontend to dar... after looking at it in more depth it > > became apparent that one would still have move the dar slices to an iso > > image and the iso image would then need to be burned. > > Obviously. But I understand it can burn them in parallel to the backup > procedure continuing. Not strictly parallel, it allows for a script to be executed after a slice has being written (or before) and one could therefore background a burn process... but if one is writing in a scenario where the media size < backup size you will get no benefit or if no of slices > 1 per media and no of media > 1 some interesting juggling will need to be performed by the script to identify what needed to be written.
I have not eliminated tar from the equation, it has more options than dar, there is a media size limit support and there does seem the possibility of piping tar output to a DVD or DVD image .... but it does use either the time stamps or an record of what has been backed up As I am no longer using tape there are a couple of options available to me that do not work with tape output.... > > > A further > > complication is although kdar apparently offers a 4Gb slice size for DVD > > the dvdtools burning tools will only accept a max of 2Gb per file > > (slice). > > Yes. I haven't looked at it for use with dar, but you know that you are > not limited to iso images for dvd burning: I myself use XFS, wich doesn't > have that limitation. I wonder I f I could use them from dar. This 2Gb file size limit seems to be a linux thing with DVDs not sure whether this is just t wodim or what. When I tried to generate an UDF image got similar problems. Optical media have somewhat different write characteristics that tend seem to make creating an image and writing the image the most effective way of using them, DVD+RW is the only media that will allow random access, and not all devices will support writing to it. > > > (And not even that... setting slice size to 2Gb still caused > > problems). > > At 2 GB, 400 MB are wasted. Better four slices of 1.1 GB. Still 400k wasted with 4Gb according to kDar (DVD slice is set as 4.3Gb) > > > To get a listing from a dar rquires access to first and last > > slices, this would suggest the for an N slice backup one would need (N > > mod 2) + (N div 2) DVDSs for a two slice solution with first DVD > > containing slice 1 and slice N, kdar provides no mechanisms for such > > slice management across media. While a bulk restore would be ok do not > > think this would work to well for retrieving a single file (one would > > not only have to know which slice a file was in but which DVD, and > > heaven forbid if the file is split between two slices on two DVDs). dar > > has some other limitations as well which took it out of picture.... > > I still have to evaluate dar, but I should think it makes an index to > facilitate this. Any good backup solution should handle this. External index an option, but then one has to transfer the index to DVD to make it available. (loops within loops) And it does not deal with issue of which part of the media set a particular file is on. > > I miss pctools backup from 198X-190X, for MsDos... it could backup to > floppies files way larger than a single floppy, and restore without > problems - even with media errors. My backups from that era still work. > But beware the dodgy floppy ;-) [ Stuff deleted ] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
