Help with backup scheme please

[dsmith]

Hello,

 

We have recently purchased a new backup tape drive and Retrospect, and I am now trying to figure the best way to perform my backups. Here is a description of what we were previously doing:

daily backup onto tape

every backup erased previous data on the tape

tapes were labelled "monday" "tuesday", etc

used a 10 tape rotation: mo, tu, wd, th, friday1, friday2, friday3, month1, month2, month3 (we always had a complete backup of files going back 3 months)

 

Currently I am using the New Media backup in Retrospect. But this appears seems awkward. When I go to do a new backup on last week's tapes it looks like I need to delete the previous backup set. The naming of the tapes is always increasing which makes it confusing which tape is which.

 

Ideally I just want to have each tape have a name that does not change. So every Monday I put in tape "backup 001" and I know this is Monday's tape. If a few days later I need to restore a file, I grab "backup 001", go to the backup set "backup 001" in Retrospect and restore my file. At this point in time I really don't know the best way to come close to this. Should I stick with "new media" backups and do something about the tape naming? Or do I move to some other type of backup like "recycle"?

 

Any help or suggestions are appreciated.

 

Regards,

Doug

[BillIrwin]

Doug:

Old habits die hard. You're using the same rotation scheme I used before moving to Retrospect over five years ago. I recommend that you first decide how much data you're willing to lose in the event of a disaster, like your office becomes a smoking crater. The answer to this question will determine your set rotation off-site.

 

If you're willing to lose a week's data, then have a minimum of three backup sets. This ensures that all sets are never on site simultaneously. Each set should have enough tape members to contain a month's worth of one master and incrementals. Name them Set 1, Set 2, Set 3. The tapes will become 1-Set 1, 2-Set 1, 1-Set 2, 2-Set 2, etc. One of the biggest benefits of using Retrospect is its ability to append incrementals so that you're not wiping out data every time a tape is used.

 

Set one script to use all sets, with a schedule to use each set daily every 3 weeks. Retro weeks start on Sunday, so Set 1 would start last Sunday. Set 2 would start this Sunday, and Set 3 the following Sunday.

 

Each set will get used every three weeks, for 7 days. Decide how many uses you want each set to have before you do a Recycle. The longer between Recycles, the more tapes each set will need, but the more history you'll have available. If you decide on four uses per set, then that's 4 X 3 = 12 weeks. Add three Recycle backups to your script's schedule (you don't need a new script) that each run every 12 weeks, one for each of the three sets. If you set the time to be the same they will replace the Normal backup that's scheduled for that day.

 

Without the ability to set which day the week should start on, it gets tricky if you want to rotate sets Mon - Fri. You want someone to be taking a set off site each week so you have something to build from in the smoking crater scenario. But the sets don't change until Sun.

 

The remedy is to split each set's schedule into two pieces. One runs Fri - Sun to Set 1, then another that runs Mon - Thu to Set 1. On Thu. you'll be prompted for a Set 2 tape, which is scheduled Fri - Sun, with Mon - Thu following.

 

To summarize, each set will have three schedules: Sat - Sun every 3 weeks; Mon - Thu every 3 weeks; Recycle on Fri every 12 weeks. You can adjust this if you want to rotate sets on a day other than Fri. In fact, if a Recycle is likely to fill a tape, then you should switch sets before Fri. so that you can put in the 2nd tape on Fri. Otherwise you won't get a backup until Tue., after the tape is replaced on Mon. I'm assuming your backups run early morning.

 

If you set the Recycle jobs to be a few weeks apart, over time you'll have much more history available than the three months you had before. Also, you can specify the file name that the user says is now corrupt, select all backup sets, and be given choices based on when the file was modified over the last few months on which version you want to restore. Once you select the version you'll be told which tape to supply. This is all done from the cataloges that are kept on disk.

 

It took me a while to get over not switching tapes every day. When a tape fills during a backup, and nobody's there to change it, you can do it the next day and the next backup will get the files that were missed. Or you can manually skip to the next set member when you're nearing capacity, but this requires monitoring things, as I don't believe there's an advance warning that there's not enough capacity to hold the next backup, since it doesn't know how much data that's going to be until the job is running and the scan has been done. I just switched tapes when one fills.

 

I hope this sets you on a path of clearer understanding on how Retrospect can make your backup management a much easier task.

 

Bill

[dsmith]

That's quite a post Bill.

Seeing how I'm also in Vancouver, I should have just contracted you to come over and set this up for me, you could have made some $$!

 

I'll have to re-read this a few times to digest it all, and I may have a few questions for you. Thanks for taking the time to repond, I appreciate it.

 

Doug

[BillIrwin]

You're very welcome Doug. When I looked at the time when I finished (2 AM) I asked myself if this couldn't have waited until the morning. Oh well ... I always have worked better later in the day.

 

Actually, I'm in North Vancouver. Although, with UltraVNC and a broadband Internet connection, I do virtually all of my clients' administration from my home office, so location isn't really an issue ... as long as I have someone on site to switch media for me.

 

Feel free to contact me directly at e-mail "bill AT eims DOT ca". Or 604.924.3467.

 

Regards,

Bill