jrowney Posted May 5, 2002 Report Share Posted May 5, 2002 Hi, I am looking for reccomendations for a simple backup strategy for my home PC. I have a 20Gb (USB) Travan drive as my backup medium. The disk has about 7-8 Gb of files on it (which took over 12 hours to back up and verify to the tape when I first tried it), but the overall content of these files does not change very much. Primarily, I would like the backups to prevent against the "total data loss" scenario (as oppesed to data archival). I have seen various strategies discussed in the forums here involving some kind of tape rotation. I must admit, I was considering using two tapes on alternating days, and only performing a recycle when a particular tape was full. I would appreciate some advice as to something a little bit more "scientific". I would certainly like to minise the number of times I need to do these half-day backups! TIA John Link to comment Share on other sites More sharing options...
jwarthman Posted May 5, 2002 Report Share Posted May 5, 2002 John, If you perform incremental backups, they're really only painful whenever you create a new backup set. At other times, the backup should run relatively quickly because only new & changed files are backed up. With Retrospect, you need not recycle your tape when it gets full. Instead, allow Retrospect to continue your incremental backup onto another tape (or two or three, or more!). That way, you won't need to take the time to do a completely new backup each time a tape fills up. Your strategy of alternating backup sets every day is a good one. Many methods exist for how to best do this. I feel that it's best to have more, not fewer, backup sets. Suppose you have seven backup sets instead of two. Each day the incremental backup will notice the changes to your hard drive for the past week, and bring the backup set current. Should you need to restore and discover the latest backup set is somehow corrupt, you can fall back to the backup set from a day earlier. If that one's broken too, you can fall back again, etc. for however many backup sets you choose to maintain. A good place to begin making your own plan is by reading all the Dantz materials on this. You may not wish to do it just the way they suggest, but you should at least become acquainted with the various backup strategies they describe. Hope This Helps! -- Jim Link to comment Share on other sites More sharing options...
pfyfe Posted May 7, 2002 Report Share Posted May 7, 2002 >Should you need to restore and discover the latest backup set is somehow corrupt, you can fall back to the backup set from a day earlier. If that one's broken too, you can fall back again, etc. for however many backup sets you choose to maintain.> I suspect most would rate this reasoning fairly low unless they were forced to back up to a unreliable medium. Note that the argument for this reasoning is only that the backup set is 'somehow' corrupt, not the files, since Retrospect can restore any of the last seven day's files if only one backup was being done. Three backup sets, one always offsite would seem to cater for 99% of our paranoia about set failure and fire. I guessed that John might have been trying to keep his costs down, hence the rotation of two tapes; certainly multiple tapes is the way to go in order to minimise time doing recycles. There is a limit there too, depending on your situation. Noone wants to be doing restores off a 7 tape set on a regular basis - there are other factors as well, regarding statistical risk and backup time. Paul. Link to comment Share on other sites More sharing options...
jwarthman Posted May 7, 2002 Report Share Posted May 7, 2002 > Note that the argument for this reasoning is only that the backup set is 'somehow' > corrupt, not the files, since Retrospect can restore any of the last seven day's > files if only one backup was being done. Not sure what your point is. Indeed, if the backup set (on tape) is intact but your catalog is not, Retrospect can rebuild the catalog by looking at the files on the tape. But it seems to me that a key reason to maintain multiple backup sets in the first place is that the backup set can become corrupt! That is, a tape may get damaged or lost or stolen, and the files on that tape would be unrecoverable. The appropriate number of backup sets is pretty much up to each person/organization. Once again, a good place to start is reading the Dantz backup strategy documents and deciding how they might be adapted to your situation. > Noone wants to be doing restores off a 7 tape set on a regular basis... If anyone is restoring "on a regular basis", there may be other issues that need attention, and the number of tapes in the backup set may be the least of their worries! :-) But seriously, if one allows the backup set to just continue to grow across multiple tapes, then a single restore can "grab" multiple versions of a single, frequently changed file. I have found that to be a great way to isolate the latest un-corrupted version of a file, when the corruption wasn't noticed right away. And yes, if one alternates one or more backup sets, such a restore should look for instances of the suspect file across multiple backup sets. Enjoy! -- Jim Link to comment Share on other sites More sharing options...
pfyfe Posted May 7, 2002 Report Share Posted May 7, 2002 >> If anyone is restoring "on a regular basis", there may be other issues that need attention, and the number of tapes in the backup set may be the least of their worries! :-) << This would be true for most home users, I guess, Jim. But for someone with more than a few computers to worry about, people trash files that they suddenly need again, regular test restores are needed to ensure reliability and comprehensiveness, a new fast computer can invoke a hand-me-down which necessitates several major restores etc. But this is a bit off-topic... Paul. Link to comment Share on other sites More sharing options...
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