HP Compaq Integrated Smart Array Controller - Manual (Page 121)

Understanding Drive Arrays B-15
Compaq Confidential – Need to Know Required
Writer: CDresden Project: Compaq Integrated Smart Array Controller User Guide Comments:
Part Number: 153236-001 File Name: i-appb Understanding Drive Arrays.doc Last Saved On: 8/27/99 11:35 AM
It is not necessary for all logical drives in an array to be the same size or even
have the same fault-tolerant configuration. Each logical drive is treated as a
separate entity no matter how many physical drives it crosses. Each may be
configured as best suits your needs.
It is important to remember that all physical drives in an array should be the
same size (capacity), because each drive contains an equal portion of one or
more logical drives, and the portion sizes can only total the size of the smallest
drive. While you are not prevented from expanding storage capacity with
larger drives, the extra space cannot be used.
During expansion of an array with two or more logical drives, the
redistribution of data takes place one logical drive at a time. When the capacity
expansion has completed, any newly created logical drive becomes available.
Under Windows NT and Novell NetWare, the new logical drive can be
appended to your existing logical volume.
Online Capacity Expansion or Extension
In certain cases, the Integrated Smart Array Controller and the Array
Configuration Utility also support making storage capacity changes online,
without taking the server or storage system offline. These features are
available if the network has both:
■ Windows NT or Novell NetWare operating systems
■ Hot-plug hard drives
NOTE: Online capacity extension is available under Windows NT only.
Because the Array Configuration Utility reconfigures the Integrated Smart
Array Controller, online reconfiguration can only take place if Array
Configuration Utility is running in the same environment as the normal server
applications.
Hot-plug drives are required for online storage changes because non-hot-plug
drives require that the server be powered down to add or remove the drive. All
storage systems support hot-plug drives.