AMCC 3WARE 720-0138-00 User Manual
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Appendix A. Glossary
136
3ware Serial ATA RAID Controller User Guide for the Power Mac G5
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Controller ID number.
Unique number assigned to every 3ware
controller in a system, starting with zero.
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Create an array
. The process of selecting individual disk drives and
selecting a RAID level. The array will appear to the operating system as a
single unit. Overwrites any existing unit configuration data on the drives.
Note that in 3ware software tools, arrays are referred to as units.
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DCB.
Disk configuration block. This is 3ware proprietary RAID table
information that is written to disk drives that are in a RAID unit, single
disk, or spare. The DCB includes information on the unit type, unit
members, RAID level, and other important RAID information.
•
Delete an array.
Deleting an array (or unit) is the process of returning the
drives in a unit to individual drives. This erases the DCB information
from the drives and deletes any data that was on them. When a unit is
deleted from a controller, it is sometimes referred to as being “destroyed.”
If you want to remove a unit without deleting the data on it, do not delete
it; instead use the Remove feature in 3DM, and then physically remove
the drives.
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Destroying
. Same as deleting a unit.
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Degraded unit.
A redundant unit that contains a drive that has failed.
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Disk roaming.
When moving a unit from one controller to another, refers
to putting disks back in a different order than they initially occupied,
without harm to the data.
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Distributed parity.
Parity (error correction code) data is distributed
across several drives in RAID 5 configurations. Distributing parity data
across drives provides both protection of data
and good performance.
•
Drive ID
. A unique identifier for a specific drive in a system. Also called a
port ID.
•
Drive Number
. The SCSI number, or channel number, of a particular
drive.
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ECC.
Error correction code. ECC Errors are grown defects that have
occurred on a drive since it was last read.
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ECC Error policy
. Determines whether an error detected during a rebuild
stops the rebuild or whether the rebuild can continue in spite of the error.
Specified by the Continue on Source Error During Rebuild unit policy.
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EMS (Enclosure Management Services).
Chassis-monitoring functions
for environmental, power, mechanical monitoring, and control using the
I²C (chassis control) bus port.
•
Export a unit
. To remove the association of a unit with a controller. Does
not affect the data on the drives. Used for array roaming, when you want
to swap out a unit without powering down the system, and move the unit