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Disk Array High Availability Features
individual disks. For highest data availability, each disk in the mirrored pair must be
located in a different enclosure.
When a data disk or disk mirror in a RAID 1 LUN fails, the disk array automatically uses the
remaining disk for data access. Until the failed disk is replaced (or a rebuild on a global hot
spare is completed), the LUN operates in degraded mode. While in degraded mode the LUN
is susceptible to the failure of the second disk. If both disks fail or become inaccessible
simultaneously, the data on the LUN becomes inaccessible.
Figure 19
shows the distribution of data on a RAID 1 LUN. Note that all data on the data
disk is replicated on the disk mirror.
Figure 19
RAID 1
LUN
RAID 0/1
RAID 0/1 uses mirroring to achieve data redundancy and disk striping to enhance
performance. It combines the speed advantage of block striping with the redundancy
advantage of mirroring. Because all data is mirrored, a RAID 0/1 LUN has a storage
efficiency of 50%.
A RAID 0/1 LUN contains an even number of from four to 30 disks. One half of the disks are
primary disks and the other half are disk mirrors. The disks in a RAID 0/1 LUN are mirrored
by the disk array hardware, which automatically writes data to both disks in the mirrored
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 ...