HP StorageWorks 9100 Extreme Data Storage System administration guide V1.0.2 (AN540-96018, February 2010)

Table 2 explains disk drive states:
Table 2 Disk drive states
DescriptionState
Drive is working normally.
ok
Drive is not present (or is so badly failed that it is not detected by the controllers).
Removed
Drive is failed and cannot be used by the RAID logic used by the controllers.
Failed
Drive is working normally but the SMART self-test logic on the drive predicts that
the drive will fail in the near future.
Predict-fail
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