Are incremental CD-bakups possible?
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From: no.top.post on 19 Dec 2009 21:24 On my old system, I've only just figured out how to backup a tree by:-- mkisofs -R /mnt/p6/usr/lib | cdrecord -v fs=6m speed=2 dev=0,0 - Obviously I'd rather not have small [10% of CD capacity] dir-trees on each CD, so I'd want to serially write several dir-trees to the same CD. Apparently the above instruction does: <read the tree & convert it> AND_THEN <write the converted data to CD> So then the 2nd step would start writing from the CD beginning ? But this is too simplistic since it's seen from the messages-while-running that a fifo is repeatedly written and read. So how can I read multiple dir-trees and write them to the CD ? == TIA
From: Henrik Carlqvist on 20 Dec 2009 07:38 no.top.post(a)gmail.com wrote: > So how can I read multiple dir-trees and write them to the CD ? A few years back when I needed to archive directory trees which wouldn't fit on a single DVD I used http://scdbackup.webframe.org/main_eng.html regards Henrik -- The address in the header is only to prevent spam. My real address is: hc3(at)poolhem.se Examples of addresses which go to spammers: root(a)localhost postmaster(a)localhost
From: The Natural Philosopher on 20 Dec 2009 08:47 no.top.post(a)gmail.com wrote: > On my old system, I've only just figured out how to backup a tree by:-- > > mkisofs -R /mnt/p6/usr/lib | cdrecord -v fs=6m speed=2 dev=0,0 - > > Obviously I'd rather not have small [10% of CD capacity] dir-trees on each CD, > so I'd want to serially write several dir-trees to the same CD. > > Apparently the above instruction does: > <read the tree & convert it> AND_THEN <write the converted data to CD> > So then the 2nd step would start writing from the CD beginning ? > > But this is too simplistic since it's seen from the messages-while-running > that a fifo is repeatedly written and read. > > So how can I read multiple dir-trees and write them to the CD ? > > == TIA > > My advice, don't even try. Consider: which lasts longer, a hard drive of a user writeable optical disk? Which has more capacity, a hard drive or a user writeable optical disk Given a nightly backup, of say a 80GB drive, which costs more, a disk that last for 5 years and costs 50 quid, or 6000 optical disks, and the space to put them? My solution is massively simple. A have a second hard drive, and rdiff backs up onto it every night. Whichever disk goes, I have the other. Since the disk only gets written to selected areas at a selected time of day, even a power cut is unlikely to kill it.
From: Aaron W. Hsu on 20 Dec 2009 09:12 no.top.post(a)gmail.com writes: >On my old system, I've only just figured out how to backup a tree by:-- >mkisofs -R /mnt/p6/usr/lib | cdrecord -v fs=6m speed=2 dev=0,0 - >Obviously I'd rather not have small [10% of CD capacity] dir-trees on each CD, >so I'd want to serially write several dir-trees to the same CD. >Apparently the above instruction does: > <read the tree & convert it> AND_THEN <write the converted data to CD> >So then the 2nd step would start writing from the CD beginning ? >But this is too simplistic since it's seen from the messages-while-running >that a fifo is repeatedly written and read. >So how can I read multiple dir-trees and write them to the CD ? There are a number of options for backup, but if you need CD backups that are incremental, you can use a combination of shell scripts, find, and mkisofs to do a complete backup of each tree with a restoration script first, and then you can do incremental backups thereafter, and simply record missing files or diffs in the filesystem recorded by find. Others have probably come up with other, more sophisticated options. Aaron W. Hsu -- A professor is one who talks in someone else's sleep.
From: Douglas Mayne on 31 Dec 2009 08:37
On Sun, 20 Dec 2009 02:24:34 +0000, no.top.post wrote: > On my old system, I've only just figured out how to backup a tree by:-- > > mkisofs -R /mnt/p6/usr/lib | cdrecord -v fs=6m speed=2 dev=0,0 - > > Obviously I'd rather not have small [10% of CD capacity] dir-trees on > each CD, so I'd want to serially write several dir-trees to the same CD. > > Apparently the above instruction does: > <read the tree & convert it> AND_THEN <write the converted data to CD> > So then the 2nd step would start writing from the CD beginning ? > > But this is too simplistic since it's seen from the > messages-while-running that a fifo is repeatedly written and read. > > So how can I read multiple dir-trees and write them to the CD ? > > == TIA > IME, data written to a CD needs to be "staged" in some way. The staging directory provides the top-level directory structure for the final CD. You might be able to rig something different, but I am not aware of how to do it. Multisession optical may do something _close_ to what you want. Feel free to experiment, but be prepared to invest some time and media in making sure it is doing what you want. Here is some additional unsolicited information- FWIW. One size does not fit all when selecting an appropriate backup strategy. YMMV. I use optical discs as my primary long-term backup medium. Their durability and cost vs. capacity remains somewhat competitive when compared to magnetic devices. However, making an optical disc requires more time and effort. To minimize the time required, I use a strategy which stages the backup data from disk-to-disk-to-optical. In my case, daily snapshots are created automatically, and are allowed to accumulate in a staging directory. I can simply write them out to optical when convenient. BTW, because the data is staged, the snapshots can be "post processed," for example, I use both compression and encryption. When the final disc image is ready, it is written to optical as a single session, and then verified. Multiple copies can be made for redundancy and as necessary. Here is an earlier post about how to backup using optical media: http://groups.google.com/group/comp.os.linux.misc/msg/7522323b1a1d6fbf -- Put all of your eggs in one basket...and then watch that basket. Mark Twain |