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Need help with a new backup-strategy


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Hi,

 

I've been using Retrospect 5.6 for a couple of years now using an older DLT1 tapedrive. Now i've bought a AIT-3 tapedrive, and in a few days i will upgrade to Retrospect 6.5 with the Exchange-addon. I have approx 250Gb data to backup. (Fileservers and Exchange)

 

This is my strategy today:

 

1 backupset daily to tape

1 backupset daily to harddrive (over the network)

 

changing to new backupset and media every 1-2 months and putting the other one off-storage.

 

This is what i want to do now:

 

5 backupsets (Mon-Fri) on different tapes named mon-fri

1 backupset daily to hardrive (over the network)¨

 

My question is. When i do the first backup (Monday) it will be a full backup of 250Gb data. This will take some time, and will probably not be ready for the tuesday's execution. But, will the tuesday backup also make a full backup of the data (250Gb)? And so on until friday? This will take like forever.

 

Is this possible:

 

Monday: Full backup to tape (250Gb data) named monday.

Tuesday: Incremental backup to tape.

Wednesday: Incremental backup to tape.

Thursday: Incremental backup to tape.

Friday: Incremental backup to tape.

 

Or DO i have to make a full backup on every weekdays tape the first time?

 

I'm a bit confused here. Suggestions are very welcome.

 

Thanks in advance

 

/ Martin

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Hi

 

The key is that each backup set is a seperate entity. So if I make 5 backup sets (one for each day) that means I will have 5 complete independent backups. I could chuck 4 of the tapes into the garbage and I would still be able to do a full restore.

 

This is a good strategy because it protects you against media failure. The downside is that you have to do 5 full backups the first time around.

 

Retrospect isn't very good at just putting the incrementals on different tapes. This is by design because it wastes media and isn't really necessary anyway.

 

You might want to use a selector the first week to cut down on the amount of data. The second week you can use the "all files" selector to pick up anything that was missed.

 

Hope that helps

Nate

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Hi Nate,

 

 

 

Thanks for your fast reply. Ok, then i have to think of a new different strategy. Because of the size of data to backup a 5 backup set (one for each day) won't work. We don't have an autoloader. It will take a few days to make a full backup.

 

 

 

Please tell me if the following is correct thinking. If i stick with 2 backupsets to tape. Is this possible:

 

 

 

Set A will run Mon-Sun first week (Full backup first time, then incremental)

 

Set B will run Mon-Sun second week (Set A taken offsite). Correct?

 

 

 

In case of a malfunction on one of my servers i will always have the last week's backup offsite, correct?

 

 

 

Next,

 

 

 

these 2 sets will be running (incremental) for 2 months, me swapping between Set A and Set B every monday.

 

 

 

After 2 months i want to recycle, is this good or bad in this scenario, and how would the setup look like in that case? Recycling Set A the 9:th week and recycling Set B the 10:th week?

 

 

 

Is this correct thinking and good strategy? I would like to have more than 2 backupsets, but every full backup gonna take a few days and lots of tapes. Without autoloader this is too much job.

 

 

 

In the case above i would have data for 2 months back, right?

 

 

 

Please add comments if this is good or bad, and if i can do this any different way. What would you do in my case?

 

 

 

Thanks

 

 

 

/ Martin

 

 

 

Edit: Maybe i should add "New media" instead of recycle after 2 months to have data for 4 months instead? Is this correct thinking?

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Hi

 

Quote:

Set A will run Mon-Sun first week (Full backup first time, then incremental)

Set B will run Mon-Sun second week (Set A taken offsite). Correct?

 

In case of a malfunction on one of my servers i will always have the last week's backup offsite, correct?

 


 

Yup. Perfect.

 

Quote:

these 2 sets will be running (incremental) for 2 months, me swapping between Set A and Set B every monday.

 

After 2 months i want to recycle, is this good or bad in this scenario, and how would the setup look like in that case? Recycling Set A the 9:th week and recycling Set B the 10:th week?

 

Is this correct thinking and good strategy? I would like to have more than 2 backupsets, but every full backup gonna take a few days and lots of tapes. Without autoloader this is too much job.

 

In the case above i would have data for 2 months back, right?

 


 

If you want 2 months of backup you will actually need 3 sets. When you recycle one set you lose a months worth of backup. If you only have 2 sets that leaves you with one month.

 

There is no need to have the recycles so close together. I would run them a few weeks apart at least. This gives you the best chances for keeping your backup history.

 

Hope that helps

Nate

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Nate & Martin,

 

Our "recycles" are a daily recycle!

 

As you noted, you need three sets -

• 2 sets with backups never more then 2 days old (in case one set completely dies)

• 1 set kept that could be as old as one month (if somehow both active daily sets dies.)

 

It takes us a few days to generate a new set each month - we can incrementally backup all our computers in one day with two days of "unbacked up" data (which helps.)

 

So - it seems that the key is how long does it take to perform a full incremental backup?

 

We did find that backing up the catalog was a lifesaver!

 

A current catalog got corrupted and we were able to recover the catalog from the other daily set and lost only one backup session.

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Yes, you're right. It does take a long time ....

 

We had ran our backups onto a tape set for almost a month - and right at the end of the month, catalog got corrupted! After trying to generate the catalog (5 tapes out of 24/dual tape reader), we calculated it would have taken us 16 hours.

 

At that point, we went offsite, got the backup, and was up in 15 minutes.

 

At this point, we are thinking about a "manual" HSM strategy - backup to FireWire disk then to tape for offsite purposes.

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