Question about multiple backup sets on a single device

[natekruser]

I am running Retrospect 7.5.324/7.5.9.102 with a networked storage device. The network storage device has 1.36TB of space. Previously I created a single disk Backup Set on it capable of using up to 90% of the drive. Unfortuantely I ran into an error which corrupted the Catalog, and all attempts at a Recatalog failed.

 

Now I would like to break up the 50 or so clients that are being backed up into seperate disk Backup Sets, each with thier own Catalog file.

 

If I create 5 disk Backup sets on the same device, each able to use 90% of the space, will they still be able to intelligently groom themselves?

 

Should I instead create 5 sets each able to use only ~18-20% of the disk?

 

Any advice on how best to utilize the block of storage I have would be greatly appreciated!

[mauricev]

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The network storage device has 1.36TB of space. Previously I created a single disk Backup Set on it capable of using up to 90% of the drive. Unfortuantely I ran into an error which corrupted the Catalog, and all attempts at a Recatalog failed.

 

Now I would like to break up the 50 or so clients that are being backed up into seperate disk Backup Sets, each with thier own Catalog file.

 

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1.36 TB isn't that large for a single backup set. I'm not sure why you were unable to recatalog. That's very unusual.

 

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If I create 5 disk Backup sets on the same device, each able to use 90% of the space, will they still be able to intelligently groom themselves?

 

Should I instead create 5 sets each able to use only ~18-20% of the disk?

 

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The hard part is gauging how much each disk set will use. If one set contains clients which have 400 GB and another that has 100 GB, the one with 400 GB will reach its max even before completing.

[Lennart_T]

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Should I instead create 5 sets each able to use only ~18-20% of the disk?

 

 

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I think so.

I created two sets at 48% each. After running a week, I adjusted one set to 44% and the other to 52%, which better reflected the needed storage.

[Richy_Boy]

That would be awfully inefficient with drive space though as one backup may have finished with plenty of space remaining, yet another may run out of space in its 'slice'. If Retrospect falls to bits when you set them all to 99% utilization then I guess as maurivev says.. a good guess at the total backup quantity per group may be required.

 

I'd be interested in an EMC answer to this though as it must crop up quite a bit with people using 7.5

 

Rich

[natekruser]

I decided to go ahead and set each of the sets to 90% utilization. I figure this leaves a little more slack for the grooming to work.

 

This protects me from the (apparently freak) error I had with the catalog files by mitigating the damage a single catalog failure can cause.

 

There are some added benefits as well.

Now several users are backed up at the same time in seperate Execution Units, preventing a single larger client from holding up some of the smaller ones. Total backup time has reduced by roughly 20-40%.

Also restorations of single clients *should* be faster, as it will be pulling from a much smaller file.

 

Unfortunately I won't be able to see if there is a problem with this type of setup for a few months. As soon as the first couple of Groomings occur, and/or Retrospect explodes, I will certainly document it here.

[Lennart_T]

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Unfortunately I won't be able to see if there is a problem with this type of setup for a few months. As soon as the first couple of Groomings occur, and/or Retrospect explodes, I will certainly document it here.

 

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Why not schedule grooming so it doesn't occur when you least expect/want it?

 

I groom all backup sets during each weekend.

[natekruser]

That's an excellent suggestion Lennart. I'm still fairly new to the software, and hadn't even considered scheduling grooming to prevent an issue from ever occuring.

 

Thank you for the advice. I hate leaving things to chance particularly with data backups!