States Of A Raidyne® Disk Array; Idle" State; Build" State; Ready" State - ICP RS Series User Manual

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C.7 States of a RAIDYNE® Disk Array
An Array Drive under the RAIDYNE® operating system can assume seven different opera-
tional modes: Idle, Ready, Fail, Build, Rebuild, Expand and Error.
C.7.1 "Idle" State
This state is characterized by the fact that the redundant information of the disk array has
never been entirely created. The disk array is in this state after its first configuration and
until you quit ICPCON. If an error should occur while the array is in the build state, the array
returns to the idle state (exception: if during build mode the dedicated drive of RAID 4 fails,
the mode changes to fail).
C.7.2 "Build" State
After the disk array has been configured for the first time, it assumes the build state as soon
as you quit ICPCON. While the array is in the build state, redundancy information is calcu-
lated and stored to the hard disks of the array.
C.7.3 "Ready" State
The disk array is fully operational when in the ready state. All redundant information is pre-
sent, that is, a hard disk can fail without impairing the functionality of the disk array. This is
the normal state of a disk array. The state ready/expand indicates, that the RAID level and/or
capacity are currently migrated/expanded.
C.7.4 "Fail" State
The disk array changes to the fail state whenever a Logical Drive fails. Redundancy informa-
tion is still present, thus allowing the remaining hard disks to continue working. This state
should be eliminated as soon as possible by replacing the defective hard disk. If a so-called
Hot Fix drive has previously been assigned to a disk array with ICPCON, the controller will
automatically replace the defective drive and start the reconstruction of the data and the
redundant information. Therefore, under these circumstances the fail state is only tempo-
rary and will be eliminated by the controller itself.
C.7.5 "Rebuild" State
The disk array will assume this state after the automatic activation of a Hot Fix drive or after
a manual replacement carried out with ICPCON. The data and the redundant information
are reconstructed and stored to the new drive.
C.7.6 "Expand" State
If the capacity or RAID level of an existing disk array is changed, the disk array changes its
state into expand. As soon as the expansion or migration is completed, the state changes
back to ready.
C.7.7 "Error" State
If a second hard disk should fail while the disk array is in the fail or rebuild state, it is not
possible to continue the working session without restrictions. The disk array is still avail-
able for I/Os, but data loss and error messages on the host level are possible.
The following state diagram of the disk array summarizes the states described above and
the transitions from one state to another.