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Disk Media Set question -- bug or feature?

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I've run into some problems with Disk Media Sets. I don't know whether they're bugs or not-yet-implemented features. Or maybe I've missed something fundamental. Or maybe I'm just want them to be something that the Retrospect developers never intended them to be.

 

I think of Disk Media Sets as a better implementation of File backups for backups to hard drives. The advantage is that Disk sets break the backup into small files, instead of one huge file. That makes it practical to copy the pieces to some other drive, or to CD/DVD/etc.

 

Here's how I thought Disk Media Sets worked. The set has a number of members. Each member is a folder with a bunch of backup files. And I could have multiple members on the same hard drive, each with a max of (say) 4.7g of backups, so they're be easy to roll out to DVD.

 

So my backup hard drive would have:

 

/Retrospect

--/MyBackup

----/1-MyBackup

------ 4.7 gigs of data files

----/2-MyBackup

------ 4.7 gigs of data files

----/3-MyBackup

------ etc

 

I could have sworn that some Retrospect documentation, or maybe one of the videos, said I could have several members on a hard drive, just as above.

 

My problem: I can't get Retrospect to create more than one member on a hard drive. Okay, I can if I create a folder for each member, and let retrospect create three layers of folders under each one, but that's TUTL ("Too Ugly To Live").

 

Any suggestions? Is there some trick to creating multiple member on the same drive, but I just missed it? Is this a not-yet-implemented feature? Or should I accept that a drive has one member, period, and live with it? That does seem to work. And while eventually that folder could have a thousand or more files, I could deal with that if I had too.

 

But it seems so much cleaner to have multiple, smaller, members per drive.

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Yes, you can have multiple members on the same hard disk but we don't usually recommend it.

 

If you want to do it, then you must create a new folder at the root of the hard disk for each member and point Retrospect to that folder for each individual member.

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Doing exactly this is the only way we can get around a severe limitation with disk backup sets - the maximum size of a member is determined by the amount of space available on the drive (NFS share in our case) AT THE TIME THE MEMBER WAS CREATED. Never mind that I will be freeing space on that drive sometime afterwards - that now free space isn't available to my disk backup set, because the member is limited to that initial free space.

 

Well, you say, disks don't usually grow, and you should just assume a particular disk/share will eventually fill with .rdb files from the member. In our case, we use Sun's SAMFS to archive files to tape, creating a D2D2T solution. It would be ideal in our case if members didn't hit an artificial "ceiling" (the initially defined member maximum) but instead kept writing .rdb files unless the NFS share had no space available. With SAMFS, the oldest .rdb files simply get released from disk, to be staged back from tape when accessed. It all works rather well, except this member size maximum. It would be nice to turn this off, as right now, backups stop until I create yet another member, even though there are still hundreds of GB available (you define high and low "watermarks" to determine when to start releasing files, and how much space to free up, respectively).

 

Any chance we could see such a feature?

 

Charles

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I see what you are asking for. Not sure of the value of it. I don't see much difference between one folder with thousands of files, or thousands of folders with about 5 rdb files each. What is your purpose for putting a disk media set onto a set of dvds? How often do you want to do it?

 

Since every .rdb file is 600MB or less, they can all be transferred to cdr, dvdr, or whatever media you like. No need to make dvd sized limits on members because its already set on the .rdb files.

 

I don't think emc anticipated that transferring a disk media set onto a smaller removable media without using retrospect would be a regular occurrence, but they did anticipate it would occasionally be necessary.

 

I think you can use retrospect to copy the contents of a disk media set onto a set of dvds by using a copy backup script. I'm doing that with a tape drive.

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