HP Surestore Disk Array 12h - And FC60, Advanced User'S Manual, Page: 242 / 466

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Managing Disk Array Capacity
Managing Disk Array Capacity
During installation, a LUN structure is created on the disk array. This structure may meet
your initial storage requirements, but at some point additional capacity may be required.
This involves adding disks and binding new LUNs.
Careful LUN planning will ensure that you achieve the desired levels of data protection and
performance from your disk array. Altering the characteristics of an existing LUN such as
its size and RAID level requires unbinding and rebinding the LUN — a time consuming
process. With careful planning you can avoid having to reconfigure the disk array when
adding disk array capacity.
Configuring LUNs
The primary task in managing disk array capacity is creating the LUN structure you need.
Factors such as capacity, RAID level, and stripe segment size must be determined for each
LUN. The LUN configuration you select should be based on system environment and
application needs.
The process of binding LUNs is much like adding new disks to your system. Each LUN
appears to the host as a single hard disk drive. However, unlike conventional hard disks,
the disk array gives you the flexibility to control the size and operating characteristics of
each LUN .
When binding LUNs, consider the following:
•
Any size limitations imposed by HP-UX or LVM.
•
The maximum numbers of LUNs that can be created on the disk array is 32. Because
LUN numbering begins at 0, the highest LUN number is 31.
•
Your backup strategy. If you do unattended backup to a device such as tape, you may
want to avoid creating a LUN that is larger than the capacity of the media. This allows
you to backup an entire LUN without changing media.