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5.845 bytes |
Service Hints & Tips |
Document ID: MCGN-3S7R32 |
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PC Server 500 / 720 - RAID drives DDD, recovery procedure ineffective
Applicable to: World-Wide
Symptom
A single drive failed, but 2 RAID fixed disk drives appear as DDD (Defunct, the drive is not responding to commands). Routine recovery procedures are ineffective in bringing the DDD drive(s) back on-line.
Note
The system may have run without problems for some time.
Problem Isolation Aids
The system is a Server 500 RAID Array (8641). The system diagnostics do not fail. The RAID Administration program appears normal. More than one DASD Backplane is installed.
Fix
Background: The RAID controller requires two cables to be attached to the DASD backplane in order to maintain control of the RAID subsystem, the SCSI signal cable (wide), and a much smaller Status cable. The Backplane in Bank C must be attached to SCSI Connector Channel 1. If installed, DASD backplane in Bank D would be attached to SCSI Connector Channel 2. The same is true of the Status cables. Status connector 1 must be attached to DASD Backplane C and Status connector 2 must be attached to DASD Backplane D, if installed.
On the RAID Adapter installed in the Server 500, the signal cable (FRU P/N06H3957) and Status cables (FRU P/N06H5081) for each channel may not be connected to the same backplane. (For example: The Status cable for the Backplane in Bank C is mistakenly connected to Bank D, and vice-versa). In this case, the RAID Adapter is not communicating with the correct Backplane (but has no way of knowing this), so erroneous status information is being presented to the RAID Adapter.
Attempting to rebuild a fixed disk with the cables mis- connected in this manner will probably result in customer data loss.
In systems which have more than one DASD Backplane installed, make certain that the RAID Channel 1 (SCSI) signal cable and the RAID Channel 1 Status cable are both attached to the same Backplane (are not crossed).
SCSI-2 Fast/Wide Streaming RAID Controller, FRU P/N06H3059
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____DASD STATUS CONN._______ _________ __ __________ _____|
| | ___ ___ ||Channel 1|| |_|Channel 2|| |
| | |___||___| ______ _______ ||
| | Chan1 Chan2 ______ ________ | | | | ||
| | ______ | | | | | | | | ||
| | | | | | | | | | | | ||
| | | | | | | | |______| |_______| ||
| | |____| |_____| |______| ||
|_|_____________________ _ _______ |
||||||||||||||| ||||||||||| |____|
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Notes
1. The HMM (Hardware Maintenance Manual) S52G-9971-02, and The PC 500 User's Manual do not show the identification of the DASD Status Connectors, as shown above.
2. While the SERVER 500 and the Server 720 both use the same RAID controller and a similar Backplane, there is no Status Cable attached directly to the RAID Controller in the Server 720. In the Server 720, the Status Cable on the Backplane is daisy-chained to the Controller Card mounted behind the operator power sequence panel. The RAID controller communicates to the DASD Backplane through the micro channel bus, the system board and the Controller Card. In the Hardware Maintenance Manual Supplement for the Server 720 (S30H-2352-00) page 29, index 1, this status cable is called the System Status Cable, FRU P/N82G3617.
SAS KEYWORDS
PSY2, SERVER, 500, RAID, 8641, PSY2ADPT, 720, PSY2PART
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Search Keywords |
PSY2, SERVER, 500, RAID, 8641, PSY2ADPT, 720, PSY2PART | |
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Hint Category |
Hard Drives, Retain | |
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Date Created |
26-02-96 | |
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Last Updated |
08-01-99 | |
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Revision Date |
08-01-2002 | |
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Brand |
IBM PC Server | |
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Product Family |
PC Server 500, PC Server 720 | |
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Machine Type |
8641, 8642 | |
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Model |
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TypeModel |
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Retain Tip (if applicable) |
H132397 | |
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Reverse Doclinks |