DPM

Living with DPM - Part 2

Tim Robichaux — Tue, 16 Sep 2008 16:53:32 GMT

Lately I've been working with System Center - Data Protection Manager from Microsoft and I have to say that while it's a nice product, there are some areas that need improvement. One of the things I've been wanting to do is talk about some of the issues I've had and open up a forum to discuss those issues. To start this off, I'm taking some of the problems that I've had with DPM's tape handling.

Note: I don't want it to look like I'm just bashing DPM. I DO like parts of it. If you know of ways to resolve these issues, PLEASE let me know. I'll post those fixes as updates.

Tape Issue El Five:

Inconsistency in tracking tape movement. When I use the tape device to remove a tape or multiple tapes (since this is the only manner to eject or load tapes), DPM does not see that I’ve done anything; it never actually talks to the tape library. When I try to resync, the progress bar completes but no updated information is produced. If I re-run a Detailed Inventory, it then finds out what tape slots are actually occupied. This seems like a lot of tape movement just for DPM to see that a tape has been removed.

Tape Issue Number VI:

The whole OMID and barcode thing. I know there has been talk about getting this fixed, but it is a big stopper when I can’t erase the tapes or generate an OMID on my own to pop in there. Until this gets resolved, I’ve just turned off the barcode reader in the tape library.

Tape Issue Number 7:

I can’t figure out how to allow multiple protection groups to get written to a single tape. This may just be me missing something pretty obvious, but I would like to be able to put multiple, smaller protection groups all on one tape so that I don’t have the huge number of extra media just to back up a bunch of 600MB – 20GB protection groups.

Yes, Number 4 is missing. When I was writing this, originally, I was doing it in the heat of irritation. That leads to many things like snarky humor and missed counts.

Living with DPM - Part 1

Tim Robichaux — Fri, 12 Sep 2008 21:43:01 GMT

Note: I don't want it to look like I'm just bashing DPM. I DO like parts of it. If you know of ways to resolve these issues, PLEASE let me know. I'll post those fixes as updates.

Tape Issue Numero Uno:

No tape controls in DPM. When I am using DPM to back up data to tape in a library, it would be nice to be able to eject and load tapes using DPM, instead of having to navigate through the menus on the front of the tape library.

Tape Issue Number Two:

Lack of success at erasing ANY tape. Whenever I try to put in a new tape and erase it, it fails. It does not matter if it is a new tape, fresh from the plastic or one that has been used for backups before, I’ve never had a tape get successfully erased. As far as I know, erasing the tape using DPM is the way to get around the issues of media with no OMID.

Tape Issue The Third:

Lack of success identifying any tape. This is the situation, I have five tapes.

Tape 1 – Fresh out of the box
Tape 2 – Fresh out of the box
Tape 3 – Used on the old system (has data)
Tape 4 – Used on the old system (has data)
Tape 5 – Used on the old system (has data)

Every tape is put into the loader and then once a Detailed Inventory is run. Here are the results:

Tape 1 – Unknown
Tape 2 – Unknown
Tape 3 – Unknown
Tape 4 – Unknown
Tape 5 – Unrecognized

I try to Erase or Identify any of the individual tapes. The jobs all fail, but when a particular tape gets put back, it changes from Unknown to Unrecognized and I can “Mark as Free…” So now, I have:

Tape 1 – Unknown
Tape 2 – Free (Contains Data)
Tape 3 – Unknown
Tape 4 – Free (Contains Data)
Tape 5 – Free (Contains Data)

So now, out of 5 tapes, I have three that I can use. This seems like a lot of work with little return.

I know that DPM is supposed to be very different from traditional backup systems, but I think that the change has been too radical. It is hard to educate IT organizations to the point where they are comfortable migrating to a new technology when something as important as backups are concerned. I'm looking forward to see where Service Pack 1 will take us in the future.

DPM - Pick Your Cleaning Tape Well

Tim Robichaux — Wed, 18 Jun 2008 18:51:14 GMT

Some important things to note when using DPM. If you are told that the drive needs to be cleaned, you need to make sure that you put the right cleaning tape in there. When we got our new Autoloader (Quantum SuperLoader 3 with a DLT-V4 drive), we ordered all of the tapes we needed, including several cleaning tapes. Once the SuperLoader was loaded, we started to run with DPM and configured Agents and Disks and all the assorted sundries that a good backup scheme needs. (If you want to know more about setting DPM, I recommend this book)

Once things were setup, I noticed that the drive was reporting that it was in need of cleaning. Loading a cleaning tape through the mailslot, I followed the standard procedure of attempting to clean the drive. For some reason it kept failing, and I couldn't figure out why. After three or four attempts, I pulled the tape out and took a really good look at it and then looked at the packaging. Almost at once I saw that it was not the right cleaning tape; we had been sent the wrong tapes. Wanting to get things up and running we RMA'ed the bad tapes and overnighted the good ones. It turned out that they only had one of the tapes we needed in stock, so we had them ship it anyway.

Now that I had the right tape, I ran the cleaning procedure again, and the gnarly orange light on the front panel went away, and the LCD reported that all was well. This was not the case, however, as every tape operation I tried in DPM failed. Erase, Clean, Create Restore Point On Tape, all returned errors that the device was not ready. I tried rescanning. I downloaded the diagnostics from Quantum. I tried power cycling. Nothing worked.

As I dug further into the problem, I found that there weren't many people who had similar problems so as a last resort, I started to look up the actual error codes that I was getting. Most of them appeared to be generic errors, but when I searched for one particular error (24052), the first result from Google caught my attention.

Google Search on the Error

Looking through the post, it seemed that this person was having the same problems that I was having, but with different hardware.

Forum post that contained the information

It appears that this is not a problem with the hardware or the tapes, but rather a bug in DPM. For some reason, it looks like what is happening is that in the DPM database, when you try to clean using an incorrect cleaning tape (or the cleaning fails, I suppose), the "OperationOccuring" state in the "tbl_MM_Drive" gets stuck in a state (state 3, whatever that is) that prevents DPM from seeing that device as ready to use, even though in the Management tab, the device is being reported as idle.

While I hate to hack a database to fix a problem, that seemed to be the quickest way, so taking the advice of the post, I whipped out my l33t SQL skillz and ran an update to that row that changed the state to "0".

UPDATE tbl_MM_Drive
SET OperationOccuring = 0
WHERE DriveID = '<My Device's GUID>'

Once this code was executed, I re-scanned the Library in DPM and then erased a tape as a test. It worked, and I danced around the office, just a bit (everyone else was gone by this point).

While this is not a thing that most people would come across in the day-to-day operation, it is something that was almost a show stopper for us. Backups are extremely important- I've already used DPM to restore some accidentally deleted files -and for our peace of mind we need those tapes for off-site archiving. This fix took me a while to find, simply for the fact that ruling out the autoloader and drive takes a lot of time. Now that it's out there, I hope that anyone else who has this problem has a quicker time!