Installation guide

Glossary
Manual No. 771961 G-11
Single Controller (Simplex) Mode
A single controller attached to a set of drives that offers RAID functionality
without the controller fault tolerance inherent in dual-active mode.
Standard Disk Drive
This term refers to a hard disk drive with SCSI, IDE, or other interface, that
is attached to the host system through a standard disk controller.
Standby Replacement of Disks (“Hot Spare”)
The “Standby Replacement” (or “Hot Spare”) is one of the most important
features the controller provides to achieve automatic, non-stop service with a
high degree of fault-tolerance. The rebuild operation will be carried out by
the controller automatically when a disk drive fails and both of the following
conditions are true:
• A “standby” disk drive of identical or larger size is found attached to
the same controller;
• All of the system drives that are dependent on the failed disk are
redundant system drives, e.g., RAID 1, RAID 3, RAID 5, RAID 0+1.
☛ Note
The automatic rebuild will only happen on the SAME
controller, never across controllers.
A “Hot Spare” disk can be created in one of two ways:
1. When configuring via a Mylex configuration utility, all disks attached
to the controller that are NOT configured into any disk array will be
automatically labeled as hot spare drives.
2. A disk drive may also be added (attached at a later time) to a running
system and labeled as a hot spare.
3. The controller creates the hot spare.
During the automatic rebuild process, system activity continues as normal.
System performance may degrade slightly during the rebuild process.