User`s guide

68 007-4522-003
4: Using the RAID Controller
modified for the intended application; see the documentation for the management
software included with the storage system for information on controller parameters.
Note: Changes to the controller parameter settings take effect after the controller is
rebooted.
System Drives
System drives are the logical devices that are presented to the operating system. During
the configuration process, after physical disk drive packs are defined, one or more
system drives must be created from the drive packs. This section discusses system drives
in these subsections:
• “System Drive Properties” on page 68
• “System Drive Affinity and Programmable LUN Mapping” on page 69
System Drive Properties
System drives have the following properties:
• The minimum size of a system drive is 8 MB; the maximum size is 2 TB.
• Up to 16 system drives can be created.
• Each system drive has a RAID level that is selectable (subject to the number of disk
drives in the system drive’s pack).
• Each system drive has its own write policy (write-back or write-through); see “Data
Caching” on page 50 for an explanation of this feature.
• Each system drive has its own LUN affinity. This capability is further discussed in
“System Drive Affinity and Programmable LUN Mapping” on page 69.
• More than one system drive can be defined on a single drive pack (LUN).