Sun Microsystems Sun StorEdge T3, Инструкция по установке, эксплуатации и обслуживанию

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Chapter 3 Operation 3-3
3.2 Reconfiguring the Disk Tray Settings
The disk tray has been set with the following default configuration:
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RAID 5 volume; no hot spare
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Cache mode set to auto
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Autodisable and autoreconstruction of disk drives
These default settings and other possible configurations are described in the
following sections. After reading this information, if you determine that you would
like to use a different configuration for your environment, refer to the Sun StorEdge
T3 Disk Tray Administrator’s Guide for instructions on how to change the disk tray
settings.
Some of the terminology as used in this chapter is defined as follows:
■
Volume, also known as a logical unit (LUN), is the basic structure you create
across the drive group to retrieve and restore data. A volume is a set of physical
drives that has been configured into RAID level 0, 1, or 5.
■
Hot spare is a drive containing no data that acts as a standby in case another drive
fails in a RAID 1 or 5 volume. The hot spare drive adds another level of
redundancy; if a drive fails, the hot spare takes over for the failed drive until you
replace it. When you replace the failed drive, data from the hot spare is copied
back to the replaced drive and the hot spare returns to a standby status.
■
Parity is additional information stored along with the data that enables the
controller to rebuild data after a drive failure. Only RAID 5 volumes have parity.
RAID 1 uses mirroring, not parity, which enables the controller to reconstruct data
after a drive failure.
3.2.1 Unit Volume Configurations
The drives in a unit can be grouped into one or two volumes (LUNs). The minimum
number of drives to compose a volume is two; the maximum is nine. A hot spare
drive can be configured in the unit as an option. If you are configuring a hot spare in
the volume, you can use only drive 9 in the disk tray as a hot spare. You can have
only one hot spare per disk tray, which can be shared by two volumes.
If you choose to include a hot spare disk drive in your configuration, add it when
you initially create the volume. If you want to add a hot spare at a later date, you
must remove the existing volume and re-create the configuration.
You can also configure the two volumes into smaller partitions or combine multiple
volumes into a single volume by using specialized third-party software such as
VERITAS Volume Manager.