IBM DCS9550 1S1 manual Troubleshooting and Problem Solving, Emulation Limitations

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Troubleshooting and Problem Solving

The DCS9550 1S1 Storage Expansion Unit includes a processor and associated monitoring and control logic to enable it to diagnose problems within the enclosure’s power, cooling and drive systems. The Enclosure Services Processor is housed along with the Ops Panel in the rear of the enclosure. The sensors for power and cooling conditions are housed within the Power Supply/Cooling modules. There is independent monitoring for each unit. If a fault is indicated on the Ops Panel, please refer to Table 4–2.

4.1Emulation Limitations

Each SCM presents each SATA disk drive as a single ported FC device. However unlike real FC-AL device certain data such as emulated WWN is not available on Power On, so the emulated devices will not present on the FC loop and participate in FC loop initialization until the drive has spun up. Please note that your RAID Head/Host system needs to be aware of this extra spin up time during Power On situations, whether they be planned ON or NOT ON (e.g. as the result of an unexpected power interrupt). Where some features, such as mode pages are not directly supported these will be emulated by the device, but changing these mode pages may not cause a change in the drive’s behavior, Where an equivalent function exists, e.g. SMART data, the ATA SMART data will be presented to the Host through the CF SCSI command set.

4.2Initial Start-up Problems

4.2.1Faulty Cords

First check that you have wired up the subsystem correctly. Then, if:

•cords are missing or damaged

•plugs are incorrect

•cords are too short

Call your supplier for a replacement.

IBM System Storage DCS9550 1S1 Storage Expansion Unit Installation, Service, and User Guide 37