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Managing Disk Array Capacity
the RAID level used by a LUN, you must unbind the LUN and rebind it using the new RAID
level.
With the exception of RAID 0, all RAID levels supported by the disk array provide
protection against disk failure. However, there are differences in performance and storage
efficiency between RAID levels. For more information on RAID levels and their
comparative operating characteristics, see
"RAID Technology" on page 47
.
The two factors that will influence the RAID level you select are performance and storage
efficiency.
•
Performance - The performance characteristics differ for each RAID level. The types
of applications you are running and the I/O activity associated with them should
influence the RAID level you select for a LUN. The performance characteristics for each
RAID level are summarized in
"RAID Level Comparisons" on page 57
.
•
Storage Efficiency - the storage efficiency can range from 50% for RAID 1 and 0/1 up
to > 80% for RAID 5. The higher the efficiency, the less cost per megabyte for storing
your data.
Global Hot Spares
Global hot spares provide additional protection against disk failures. The number of global
hot spares you use will reflect how much protection you need. Each global hot spare you
add will provide protection against the failure of a single disk. In addition to restoring
hardware redundancy, a global hot spare also restores disk array performance that may be
diminished while the disk array is operating in degraded mode with a failed disk.
When adding global hot spares, consider the following:
•
It is recommended that you add one global hot spare per disk channel. This provides
maximum protection against disk failure. A global hot spare can be used to replace any
failed disk within the array, regardless of what channel it is on.
•
When a failed disk is replaced, the data will be copied from the global hot spare disk to
the replacement disk and the global hot spare will again be available as protection
against another disk failure.
Summary of Contents for Surestore Disk Array 12h - And FC60
Page 16: ...16 ...
Page 36: ...36 Array Controller Enclosure Components Figure 9 Controller Enclosure Front View ...
Page 41: ...Array Controller Enclosure Components 41 Product Description Figure 13 Controller Fan Module ...
Page 44: ...44 Array Controller Enclosure Components Figure 15 Power Supply Fan Module ...
Page 68: ...68 Capacity Management Features ...
Page 117: ...Topologies for HP UX 117 Topology and Array Planning Figure 39 High Availability Topology ...
Page 122: ...122 Topologies for HP UX Figure 40 High Availability Distance and Capacity Topology ...
Page 126: ...126 Topologies for HP UX Figure 41 Campus Topology ...
Page 130: ...130 Topologies for HP UX Figure 43 Four Hosts Connected to Cascaded Switches ...
Page 142: ...142 Topologies for Windows NT and Windows 2000 ...
Page 158: ...158 Installing the Disk Array FC60 Figure 54 Enclosure EIA Positions for System E Racks ...
Page 161: ...Installing the Disk Enclosures 161 Installation Figure 56 Disk Enclosure Contents ...
Page 172: ...172 Installing the Controller Figure 62 Controller Enclosure Package Contents ...
Page 174: ...174 Installing the Controller Figure 63 Mounting the Controller Enclosure ...
Page 234: ...234 Adding Disk Enclosures to Increase Capacity ...
Page 274: ...274 Managing the Disk Array Using SAM Unassigned disks selected as hot spares ...
Page 345: ...HP UX Diagnostic Tools 345 5 HP UX DIAGNOSTIC TOOLS Overview 346 Support Tools Manager 347 ...
Page 350: ...350 Support Tools Manager Figure 90 mstm Interface Main Window ...
Page 358: ...358 Support Tools Manager ...
Page 440: ...440 FCC Statements USA Only ...
Page 466: ...466 Index ...