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Disk Array High Availability Features
Settings that give a higher priority to the rebuild process will cause the rebuild to complete
sooner, but at the expense of I/O performance. Lower rebuild priority settings favors host
I/Os, which will maintain I/O performance but delay the completion of the rebuild.
The rebuild priority settings selected reflect the importance of performance versus data
availability. The LUN being rebuilt is vulnerable to another disk failure while the rebuild is
in progress. The longer the rebuild takes, the greater the chance of another disk failure.
The following sequence occurs following a disk failure and replacement.
Figure 23
illustrates the process. A 5-disk RAID 5 LUN is used for this example.
1. Disk 3 in the RAID 5 LUN fails.
2. The disk array locates an available global hot spare and begins recreating on it the
information that was on the failed disk. The data and parity on the remaining four disks
in the LUN are used to recreate the information.
3. When the rebuild finishes, the global hot spare is part of the LUN, which fulfills the roll
of disk 3.
4. When disk 3 is replaced, the disk array begins copying all the information from the
former global hot spare to the replacement disk.
5. When copying completes, the LUN is restored to its original configuration. The former
global hot spare is returned to the global hot spare disk group and is available to protect
against another data disk failure.
Note
Can a lower capacity disk serve as a hot spare for a larger disk?
It is possible for a lower capacity disk to be used as a global hot spare when a
larger disk fails. When a disk failure occurs, the disk array controller looks for
a global hot spare that is large enough to store the data on the failed disk, not
for a disk that matches the capacity of the failed disk. For example, if an 18
Gbyte disk fails but there is only 6 Gbytes of data stored on the disk, a 9 Gbyte
global hot spare could be used.
Although this feature is available, it is recommended that you always select the
largest disks in the array to serve as global hot spares. This will ensure that any
disk in the array is protected, regardless of how much data is stored on it.
Содержание Surestore Disk Array 12h - And FC60
Страница 16: ...16 ...
Страница 36: ...36 Array Controller Enclosure Components Figure 9 Controller Enclosure Front View ...
Страница 41: ...Array Controller Enclosure Components 41 Product Description Figure 13 Controller Fan Module ...
Страница 44: ...44 Array Controller Enclosure Components Figure 15 Power Supply Fan Module ...
Страница 68: ...68 Capacity Management Features ...
Страница 117: ...Topologies for HP UX 117 Topology and Array Planning Figure 39 High Availability Topology ...
Страница 122: ...122 Topologies for HP UX Figure 40 High Availability Distance and Capacity Topology ...
Страница 126: ...126 Topologies for HP UX Figure 41 Campus Topology ...
Страница 130: ...130 Topologies for HP UX Figure 43 Four Hosts Connected to Cascaded Switches ...
Страница 134: ...134 Topologies for Windows NT and Windows 2000 Figure 45 Four Host Single Hub Single Disk Array Non HA Topology ...
Страница 136: ...136 Topologies for Windows NT and Windows 2000 Figure 47 Four Host Single Switch Dual Disk Array Non HA Topology ...
Страница 138: ...138 Topologies for Windows NT and Windows 2000 Figure 48 Direct Connect Single Host Single Disk Array HA Topology ...
Страница 140: ...140 Topologies for Windows NT and Windows 2000 Figure 50 Four Host Dual Hub Dual Disk Array HA Topology ...
Страница 142: ...142 Topologies for Windows NT and Windows 2000 ...
Страница 158: ...158 Installing the Disk Array FC60 Figure 54 Enclosure EIA Positions for System E Racks ...
Страница 159: ...Installing the Disk Array FC60 159 Installation Figure 55 Enclosure EIA Positions for Legacy Cabinets ...
Страница 161: ...Installing the Disk Enclosures 161 Installation Figure 56 Disk Enclosure Contents ...
Страница 172: ...172 Installing the Controller Figure 62 Controller Enclosure Package Contents ...
Страница 174: ...174 Installing the Controller Figure 63 Mounting the Controller Enclosure ...
Страница 234: ...234 Adding Disk Enclosures to Increase Capacity ...
Страница 274: ...274 Managing the Disk Array Using SAM Unassigned disks selected as hot spares ...
Страница 345: ...HP UX Diagnostic Tools 345 5 HP UX DIAGNOSTIC TOOLS Overview 346 Support Tools Manager 347 ...
Страница 350: ...350 Support Tools Manager Figure 90 mstm Interface Main Window ...
Страница 358: ...358 Support Tools Manager ...
Страница 401: ...Controller Enclosure Modules 401 Removal and Replacement Figure 101 BBU Removal and Replacement ...
Страница 440: ...440 FCC Statements USA Only ...
Страница 466: ...466 Index ...