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In preparation for adding a number of 1Tb SATA disks to our DS4700 I flashed the controller firmware from a 6 series (which only supports up to 2Tb logical drives) to a 7 series (which supports larger than 2Tb logical drives). Attached to this DS4700 was a EXP710 expansion drawer that we had planned to migrate out to our co-location to allieviate the storage issues we were having there. Unfortunately these two projects were planned in isolation to one another so I was at the time unaware of the issue that this would cause. Prior to migrating the drawer I was reading the "IBM TotalStorage DS4000 EXP700 and EXP710 Storage Expansion EnclosuresInstallation, User’s, and Maintenance Guide" and discovered this: Controller firmware 6.xx or earlier has a different metadata (DACstore) data structure than controller firmware 7.xx.xx.xx. Metadata consists of the array and logical drive configuration data. These two metadata data structures are not interchangeable. When powered up and in Optimal state, the storage subsystem with controller firmware level 7.xx.xx.xx can convert the metadata from the drives configured in storage subsystems with controller firmware level 6.xx or earlier to controller firmware level 7.xx.xx.xx metadata data structure. However, the storage subsystem with controller firmware level 6.xx or earlier cannot read the metadata from the drives configured in storage subsystems with controller firmware level 7.xx.xx.xx or later.

I had assumed that if I deleted the logical drives and array information on the EXP710 prior to migrating it to the DS4300 (6.60.22 firmware) this would satisfy the above, unfortunately I was wrong.

So my question is a) Is it possible to restore the DAC information to its factory settings, b) What tool(s) would I use to accomplish this, or c) is this a lost cause?

Daniel.

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3 Answers 3

I'd suggest you raise this with the people that provide support for your DS's so they can provide you with a conclusive answer

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The method to downgrade firmware is discussed at:

http://www.ibm.com/developerworks/forums/thread.jspa?threadID=234781

Another approach I might suggest, is that some sites keep spare controllers on hand. Refurbished controllers are available for much less than list. The spare would hopefully be loaded with a 6.nn.mm version. For this task, you only need one controller: the redundancy is not necessary.

Or can you rebuild from a backup? Good Luck!

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Do you need to retain the information on the drives?

If not, initializing them on the DS4300 should wipe out the data and old DAC.

If this doesn't work, just do it by hand. Hook a server with a FC HBA directly to the expansion shelf and zero the drives. They will then be treated by the DS4300 as new drives.

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He mentioned that he already cleaned the data off, but simply can't read the new drives with his 4300. –  Basil Oct 3 '11 at 1:07
    
He said he deleted the logical drives and array info - that's not cleaning the data off. He'll need to zero them out. –  MikeyB Oct 3 '11 at 14:42

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