Grandfather father son

[rob_gf]

I am trying to do a grandfather father son rotation in retrospect, but I can't see how to do an incremental or differential backup.

 

 

Running Retrospect 7.6 on windows 2003 Standard with 20 windows client machines.

 

[Daniels]

A Normal Backup is the same as an incremental backup so for incremental backups you need to select Normal Backup.

[demani]

As far as scheduling these goes, I usually let the daily and weekly scripts run all the time (so they will only run if their media is in place- helpful if calamity ensues the day you were supposed to bring the tapes in and it doesn't happen that day). Monthly are manually kicked off.

 

It does help if you can A) preconfigure your tapes for each set so you can turn off use new media automatically if a current member isn't found (otherwise a blank tape will get used instead of the script getting skipped). And make sure to set the script timeout.

[rob_gf]

OK I'll try and explain this the best way I can.

 

I started out with 8 backup sets. Week 1 -4 and monday - thursday.

 

Week 1 was on a Friday and requires 2 LTO2 tapes and is set as recycle (which I understand to be a full backup next time around). The Monday tape then runs as a normal backup but backs up everything again. I want it to just take and changed or additional files since the Week 1 backup ran.

 

[Daniels]

Incremental/Normal backups will only compare what has changed to what is actually on the required media. However in order to get a starting point Retrospect needs to make a full backup on each media set. After doing this it will then do an incremental backup each time the media set is used. Each new media set will have to have at least one full backup as a starting point otherwise there is way to compare what has changed since the last time the media was used.

[rob_gf]

Okay, if start out creating a Week 1 backup set and run a full backup on Friday, then monday - thursday I run a new member action. So my 1-week 1 is a full backup and my daily backups (2-week 1, 3-week etc.)are all in the same backup set. That way Friday should do a recycle backup which is a full backup, and then monday will just backup any changes or additions, same with tuesday, wednesday etc.

 

Would this work?

[Daniels]

I never explored using a new member backup but from what I understand is that if the tapes are all in the same media set then each additional tape would only be an incremental/normal backup.

[rob_gf]

I am curious to see if someone has tried this before. What would happen to the monday tape on the second week. Would retrospect still look for 2-Week 1 or would it require a new member again, or would it look for the first member in the set with room available. Seems very tricky to configure.

 

I guess I will have to try it out. I will keep you posted.

[Daniels]

Since a recycle backup resets the media set it sees the media set as only having the number of tapes used on Friday so I think it would want to create a new member numbered x+1. If you tell it to automatically reuse named media it may use 2-week 1 as its member but like I said I have never tried new media member backups.

[demani]

My understanding is that there is no way to do what you are looking to do- Retrospect does full and Incremental, but not differential backups. That is both a blessing and a curse.

 

Differential backups let you have multiple branches (the dailies) off one trunk (the weekly). A backup from any day would be two tapes: the weekly and the daily. To restore you would first do a restore from the weekly, then overlay it with a restore from the daily.

 

Retrospect only does incrementals, so each daily has to have one full pass first, then it does incrementals after that. The advantage of this is that only the one set is needed, and only one restore is needed to take place.

 

To do what you want, you should create 4 weekly scripts, and set the schedules for those so they run every 4 weeks. The first time you put them in they will do a full backup. But every subsequent time they will only need to update with the files that changed over the last 4 weeks.

 

The dailies would also be set similarly (though again, I would have them all set to run every weekday, and to time out after 10 minutes, but not to jump to new media so you can be sure a backup will still run if you are out sick). The first time each runs it will do a full backup. However, I would not recycle the set after the first time: get a second tape for each daily set. Since its highly unlikely you will churn the server 100% every week, you can use that second tape (e.g. 2-Monday) as your daily and rotate it offsite with the first tape (1-Monday). You can do that until the second tape fills, then just recycle the set.

 

If you aren't rotating the dailies offsite you could just stick with 4 weekly sets, and let them run daily backups. Because of the snapshots Retrospect provides you would be able to go back and pick a restore point for each day during the week. For many people this serves the same purpose as daily differentials, and allows you to only need to rotate your sets weekly. This also leads to less frequent rotation of tapes in the drive (though you should probably still monitor the backups daily to see when new tapes are needed). You can extend a set's historical reach by adding an extra tape. I use this so I can stagger the recycle period (4 sets all being rotated regularly will result in all 4 getting recycled around the same time- one extra member in one set will let that one live longer, so you can keep a longer trail of data).