paulrs Posted March 25, 2003 Report Share Posted March 25, 2003 RE: OS X 10.2.4, Retrospect 5.0.238 All, I'm trying to understand how Retrospect manages information on removable tapes. My only backup experience has been with DDS I & DDS II drives under NeXTstep and OpenStep using dump and restore. With dump & restore, I had a backup schedule with 1 tape for each day of the week from Mon - Thur and then 3 rotating tapes for Friday and 4 rotating tapes for every fourth Friday. With OS X and Retrospect, I am using a VXA tape drive with 60-120 GB tapes that cost at least 60 USD each. Even if I do a full/non-incremental backup of all my drives, I probably need only about 10GB of uncompressed space. What I can't seem to figure out from the documentation and online tutorials that I have read is whether I need to purchase a separate tape for each backup set. I realize, or at least I think I realize that tapes are not like hard drives in that data on a tape must be contiguous and cannot be spread around or randomly accessed like it can on a hard drive. So, just because I need only 10% of the total capacity of a tape for any given day, doesn't mean I can expect the backup software to be able to re-use the same media for multiple backup sets. However, compared to my DDS days, it is prohibitively expensive to buy so much tape media to support the kind of backup rotation to which I am accustomed, so I'm hoping that maybe I am missing something and that there is a way to reuse the same media for multiple backup sets. If anyone can point me in the right direction, I would greatly appreciate it. Best Regards, Paul Link to comment Share on other sites More sharing options...
AmyJ Posted March 25, 2003 Report Share Posted March 25, 2003 Each backup set will require it's own unique tape(s). The goal of multiple backups is to provide you with that extra layer of security. You can keep backup sets off site, and rotate them so that if a tape goes bad or your building burns down you've got additional backup sets to restore from. Putting multiple sets on a tape would only negate the goal of redundant backups. If you are doing normal (incremental) backups, you may find the extra capacity helpful in that the sets will continue to grow with each backup. Incremental backups append to the end of the existing tapes. The great thing about Retrospect is that you don't need a full backup each time to restore your system back to a prior state. If you create a Monday backup set and use it every Monday for a month, the first backup will be a full backup. Each subsequent Monday only the changes will be backed up. Should you need to do a full system restore, you can pick any of the Mondays and have Retrospect put the system back into that state with one exectution - a one shot restore. You don't have to restore your full backups, and then each individual session as you do with other backup programs. VXA also offers lower capacity tapes that may better fit your needs. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.