HP NetRAID 1 Controller - Manual (Page 67)

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Audible Warnings
HP NetRAID has an onboard tone generator that indicates events and errors.
Tone Pattern Meaning Examples
Three seconds on and
one second off A logical drive is offline. One or more drives in a RAID 0
configuration failed.
Two or more drives in a RAID 1, 3,
or 5 configuration failed.
One second on and one
second off A logical drive is running
in degraded mode. One drive in a RAID 3 or 5
configuration failed.
One second on and
three seconds off An automatically initiated
rebuild has been
completed. While you were away from the
system, a disk drive in a RAID 1, 3,
or 5 configuration failed and was
rebuilt.