On Fri, 2005-07-01 at 13:07, Mike McCarty wrote: > It seems that there are two schools of thought > > cpio > tar No, both those work only through the filesystem. Dump is the other alternative - it is excessively intimate with the disk structure. Straight dd images of the raw disk are even more extreme. > It also seems that each side thinks the other side is nuts. > It also seems that using links (soft or otherwise) is not > well handled by either technique. Gnutar and star provide extensions to the original tar (which did omit support for some essential things). > It also seems that everyone agrees that using tape is the > Way To Go(tm). Tape is OK for archiving large amounts of data that you probably don't want to restore or keeping offsite for disaster recover, which again you don't really ever plan to do... > Can anyone tell me whether my impressions on this matter > be correct? Is there a good tutorial which can give me > relative pros and cons of cpio style vs. tar style backup? Both of these copy files through the filesystem with extensions for special files. The only real difference is that tar knows how to recurse through directories itself, where cpio must be handed a list of files, generally by some contortions with 'find'. A side effect of this is that gnutar has a '--listed-incremental' mode that will catch renamed directories in an incremental and take the old files under them, where this is basically impossible with cpio. > I also don't want to use a tape drive, being (as some are) > on a restricted budget, both for time to learn new stuff > and monetarily, being among the Great Telecom Layoff. There > are very nice Windows programs which create initial/disaster > recovery CDs which can completely rebuild a system to the way > it was when initially created, and then do backups to CD after > that. *nix seems not to have any such concept. There are at least three different reasons you might want to make backups and different systems work better for the different instances and there are ways to handle compromises. If your goal is to be able to restore an exactly identical system as fast as possible you might want mondo or a disk image solution or a 'warm spare' machine with periodic rsync to it's drives. Dump is also suitable for this, along with tar/cpio archives of the whole system as long as you know a few tricks about restoring using a bootable CD, making your own filesystems and making them bootable with grub. Another goal might be to have long-term archives, in which case tar and cpio are likely to be the most portable and readable at some future date. These will also be a good option if you are rebuilding a new and better machine instead of restoring exactly the one that died, since you will have the option to restore onto different filesystem types. The most likely reason to need the backup is that someone accidentally deleted some files or directories and you are restoring back to the same machine. In this case, something online instead of tapes is a big win. If you have more than one machine involved, look at backuppc (http://backuppc.sourceforge.net/) which uses a scheme of compression an linking to keep copies on disk in a web browsable form, plus it can generate tar images of any version of any filesystem within the range you are keeping. It is as handy as you can get for the individual file/directory restores and you can do the bare-iron restores with a small amount of work. -- Les Mikesell lesmikesell@xxxxxxxxx
