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RAID Level Descriptions, RAID 0

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RAID Level Descriptions RAID levels are numbered from 0 through 6; a higher RAID level does not necessarily indicate a higher level of performance or fault tolerance. The RAID controllers support RAID levels that have proven to be the most useful for RAID applications: RAID 0, 1, 10, 3, 5, 50, and 6. You can use Non-RAID for a virtual disk that will have a single drive and not need the data redundancy or performance benefits of RAID. RAID 0 In a RAID 0 virtual disk, data is distributed, or striped, across the disk drives in the virtual disk. The virtual disk appears to the host as one large disk with a capacity approximately equal to the combined capacity of the disk drives. Because multiple reads and writes can be handled in parallel, the I/O performance of the virtual disk is much better than that of a single disk drive. RAID 0 virtual disks do not store redundant data, so they are not true RAID applications. If one disk drive fails, the entire virtual disk fails and all virtual disk data is lost. The fault tolerance of a RAID 0 virtual disk, therefore, is less than that of any single disk drive in the virtual disk. The term RAID 0 is widely used for these virtual disks, however, because they are conceptually similar to true RAID applications. RAID 1, RAID 10 In RAID 1 and RAID 10 virtual disks (commonly called mirrored virtual disks), disk drives are paired, with both disk drives in a pair containing the same data. When data is written to a mirrored virtual disk, it is written twice-once to each disk drive in the pair. A RAID 1 virtual disk has only one set of paired disk drives. A RAID 10 virtual disk has multiple pairs, across which data is striped. The read performance of RAID 1 virtual disks can be much better than that of a single disk drive, while the write performance is slightly lower. In RAID 10 virtual disks, both read performance and write performance are better than those of a single disk drive. Appendix B RAID Levels 249

Section	Page
Contents	3
About This Guide	13
Intended Audience	13
Prerequisites	13
Document Conventions	13
HP Technical Support	14
Customer Self Repair	14
Product Warranties	14
Subscription Service	15
HP Websites	15
Documentation Feedback	15
1	17
Introducing and Using SMU	17
What is SMU?	17
Preparing to Use SMU	18
Logging In and Out of SMU	19
Understanding the Interface	21
Interface Elements	21
Navigating SMU	23
Help Bar Icons	24
Virtual Disk Icons	24
System Panel	26
Help Menu	27
Size Representations in SMU	27
2	29
Configuring Your System for the First Time	29
Configuring Preferences	29
Configuring User Access	31
User Roles	31
Access Privileges	32
How User Configuration Affects the SMU Menu	32
Modifying Users	32
Adding Users	34
Deleting Users	35
Managing Licenses	35
Viewing Installed Licenses	36
Installing a License	36
Setting System Information	37
Setting Date and Time	37
Configuring Host Ports	39
Configuring FC Host Ports	39
Setting FC Host Port Link Speed	40
Setting FC Host Port Loop IDs	40
Configuring FC Host Port Interconnects	41
Setting FC Host Port Topology	42
Configuring iSCSI Host Ports	44
Configuring iSCSI Login Authentication	45
Creating a CHAP Entry	46
Viewing a CHAP Entry	47
Modifying a CHAP Entry	47
Deleting a CHAP Entry	47
Configuring Ethernet Management Ports	48
Using DHCP to Obtain IP Settings	48
Using Static IP Settings	49
Setting the Telnet Timeout	49
Setting the SNMP Event Table Filter	50
Setting the Web Page Caching Mode	51
Configuring Network Management Services	52
Configuring Event Notification	53
Enabling or Disabling Event Notification	54
Selecting Event Categories to Monitor	54
Selecting Individual Events to Monitor	55
Configuring Visual Alerts	55
Configuring Email Alerts	56
Configuring SNMP Traps	58
Changing the Cache Redundancy Mode	58
Saving the Configuration to a File	60
Restarting and Shutting Down a Controller	61
Restarting a Controller	61
Shutting Down a Controller	62
3	63
Managing Storage	63
Creating Virtual Disks and Volumes	63
Creating a Virtual Disk Automatically	65
Creating a Virtual Disk Manually	67
Virtual Disk Initialization	70
Managing Virtual Disks	71
Viewing Virtual Disk and Disk Drive Status Information	71
Virtual Disk Status	71
Disk Drive Status	73
Expanding Virtual Disk Capacity	74
Checking the Progress of a Utility	75
Removing a Virtual Disk From Quarantine	75
Verifying a Virtual Disk	76
Starting Virtual Disk Verification	77
Stopping Virtual Disk Verification	77
Changing Virtual Disk Ownership	78
Changing a Virtual Disk Name	79
Deleting a Virtual Disk	79
Managing Spares	80
Managing Dynamic Spares	80
Managing Vdisk Spares	81
Adding Vdisk Spares	81
Deleting Vdisk Spares	82
Managing Global Spares	83
Adding Global Spares	83
Deleting Global Spares	83
Displaying Global Spares	84
Managing Volumes	84
Understanding Volumes	84
Adding a Volume	86
Expanding a Volume	87
Viewing Volume Status Information	87
Changing a Volume Name	88
Changing a Volume’s Read-Ahead Cache Settings	89
Changing a Volume’s Write-Back Cache Setting	91
Changing Auto-Write-Through Triggers and Behaviors	92
Deleting a Volume	93
Managing Host Access to Volumes	94
Managing the Global Host List	95
Managing the Global Host List on an FC System	95
Managing the Global Host List on a SAS System	96
Managing the Global Host List on an iSCSI System	97
Managing Volume Mappings	99
Managing Volume Mappings on an FC System	99
Managing Volume Mappings on an iSCSI System	100
Managing Volume Mappings on a SAS System	102
Using Snapshot Services	104
Maximum Number of Snapshots	105
Estimating Snap-Pool Size	105
Reverting to Original Data	107
Creating a Snap Pool	109
Setting Snap Pool Policies and Thresholds	110
Policy Trigger Behavior	110
Creating a Master Volume	112
Creating a New Volume as a Master Volume	112
Converting a Standard Volume to a Master Volume	113
Taking a Snapshot	114
Resetting a Snapshot	115
Deleting Modified Data	115
Rolling Back a Master Volume	116
Deleting a Snapshot	118
Viewing Information About Snap Pools, Master Volumes, and Snapshots	118
Using Volume-Copy Services	121
Copying a Volume	124
Viewing the Status of a Volume Copy	125
Canceling a Volume Copy	126
Using the Scheduler	127
Creating a Take Snapshot Task	127
Creating a Reset Snapshot Task	128
Creating a Volume Copy Task	129
Viewing Task Information	130
Deleting a Task	131
Creating a Schedule	131
Viewing Schedule Information	132
Deleting a Schedule	133
4	135
Managing Disk Drives and Enclosures	135
Managing Disk Drives	135
Viewing Disk Drive Information	135
Viewing All Disk Drives	135
Viewing Disk Drive Status	136
Clearing Metadata From Leftover Disk Drives	136
Enabling or Disabling SMART Changes	137
Viewing Disk Drive Read-Cache Status	138
Illuminating a Drive Module LED	138
Viewing and Updating Disk Drive Firmware Versions	138
Viewing Disk Drive Types and Firmware Versions	139
Updating Disk Drive Firmware	139
Stopping or Aborting a Disk Drive Firmware Update	141
Managing Enclosures	142
Displaying Enclosure Status	142
Using Enclosure Management Pages	142
Viewing Enclosure Details	143
Entering Enclosure Information	143
Illuminating Enclosure LEDs	144
Changing the Enclosure Polling Rate	144
Correcting Enclosure IDs	145
Viewing Drive Enclosure Versions	145
Updating Drive Enclosure Firmware	146
Stopping or Aborting a Drive Enclosure Firmware Update	147
5	149
Monitoring System Status	149
Displaying Status Information	149
Status Summary	149
Virtual Disk Status	150
Host Port Status	152
FC Host Port Status	152
iSCSI Host Port Status	153
SAS Host Port Status	154
Disk Drive List	155
Disk Drives by Enclosure	156
Enclosure View is Unavailable	157
LAN Information	158
Module Status	159
Controller Versions	160
FRU Information	161
Enclosure Status	161
Temperature Status	163
Power Status	163
Volume Information	164
Misc Configuration	165
Expander Status	167
Viewing the Event Log	171
Viewing Statistics	171
Rate Statistics for Virtual Disks	172
Cumulative Statistics for Virtual Disks	172
Rate Statistics for Volumes	173
Cumulative Statistics for Volumes	173
Real-Time Statistics for Volumes	174
Disk Drive Error Statistics	174
Disk Space Usage Statistics	176
Resetting Statistics	177
Displaying Notification Events	178
Additional Status Information	179
6	181
Additional Configuration Functions and Utilities	181
Updating Software	181
Disabling Partner Firmware Upgrade	183
Changing Utility Priority	183
Scanning for Device Changes	184
Resetting a Host Channel on an FC or SAS System	185
Clearing Unwritable Cache Data	186
Restoring a Saved Configuration File	187
Viewing and Restoring Default Settings	188
Viewing Changed Settings	188
Restoring All Defaults	188
Enabling and Disabling Background Scrub for Disks	189
Controlling Host Access to the System’s Write-Back Cache Setting	190
Changing the Sync Cache Mode Option	190
Changing the Missing LUN Response Option	191
Configuring In-band Management Services	192
Saving Log Information to a File	192
Setting Up the Debug Log	193
7	195
Troubleshooting Using SMU	195
Problems Using SMU to Access a Storage System	196
Determining Storage System Status and Verifying Faults	197
Stopping I/O	198
Clearing Metadata From Leftover Disk Drives	199
Isolating Faulty Disk Drives	199
Identifying a Faulty Disk Drive	199
Reviewing Disk Drive Error Statistics	200
Capturing Error Trend Data	202
Reviewing the Event Logs	202
Reconstructing a Virtual Disk	203
Isolating Data Path Faults	204
Isolating Internal Data Path Faults	204
Checking PHY Status	206
Reviewing the Event Log for Disabled PHYs	207
Isolating External Data Path Faults on an FC Storage System	208
Isolating External Data Path Faults on an iSCSI Storage System	209
Isolating External Data Path Faults on a SAS Storage System	210
Resetting a Host Channel on an FC or SAS Storage System	211
Changing PHY Fault Isolation Settings	211
Resetting Expander Error Counters	211
Disabling or Enabling a PHY	212
Disabling or Enabling PHY Isolation	212
Using Recovery Utilities	213
Removing a Virtual Disk From Quarantine	213
Trusting a Virtual Disk for Disaster Recovery	213
Problems Scheduling Tasks	215
Affect of Changing the Date and Time	216
Deleting Tasks	216
Errors Associated with Scheduling Tasks	216
Selecting Individual Events for Notification	216
Selecting or Clearing All Events for Notification	218
Using Event Logs	218
Event Severities	219
Viewing the Event Log	219
Viewing an Event Log Saved From SMU	221
Reviewing Event Logs	222
Saving Log Information to a File	223
Configuring the Debug Log	224
Correcting Enclosure IDs	225
Problems After Power-On or Restart	225
A	227
SNMP Configuration	227
Introduction	227
Standard MIB-II Behavior	228
Enterprise Traps	228
FA MIB 2.2 SNMP Behavior	229
External Details for Certain FA MIB 2.2 Objects	238
External Details for connUnitRevsTable	238
External Details for connUnitSensorTable	239
External Details for connUnitPortTable	240
Configuring SNMP Event Notification in SMU	241
SNMP Management	241
Enterprise Trap MIB	242
FA MIB 2.2 and 4.0 Differences	245
B	247
RAID Levels	247
Introduction	247
RAID Level Descriptions	249
RAID 0	249
RAID 1, RAID 10	249
RAID 3	250
RAID 5	250
RAID 50	251
RAID 6	251
Non-RAID	251
Comparing RAID Levels	252
Mixing Disk Drive Models	253
C	255
Host Access to Storage	255
Node and Port Identifiers	256
FC	256
iSCSI	257
SAS	257
FC Direct Attach Configuration	258
FC Switch Attach Configuration	260
iSCSI Switch Attach Configuration	263
SAS Direct Attach Configurations	265
D	267
SMU Menu Reference	267
Standard and Advanced User Functions	267
Diagnostic User Functions	274
E	275
Event Codes	275
Disk Drive Errors and Recommended Actions	300
Power-and-Cooling Module Faults and Recommended Actions	302
Glossary	303

Match case Limit results 1 per page

Appendix B

RAID Levels

249

RAID Level Descriptions

RAID levels are numbered from 0 through 6; a higher RAID level does not

necessarily indicate a higher level of performance or fault tolerance. The RAID

controllers support RAID levels that have proven to be the most useful for RAID

applications: RAID 0, 1, 10, 3, 5, 50, and 6. You can use Non-RAID for a virtual

disk that will have a single drive and not need the data redundancy or performance

benefits of RAID.

RAID 0

In a RAID 0 virtual disk, data is distributed, or

striped

, across the disk drives in the

virtual disk. The virtual disk appears to the host as one large disk with a capacity

approximately equal to the combined capacity of the disk drives. Because multiple

reads and writes can be handled in parallel, the I/O performance of the virtual disk

is much better than that of a single disk drive.

RAID 0 virtual disks do not store redundant data, so they are not true RAID

applications. If one disk drive fails, the entire virtual disk fails and all virtual disk

data is lost. The fault tolerance of a RAID 0 virtual disk, therefore, is less than that

of any single disk drive in the virtual disk. The term RAID 0 is widely used for

these virtual disks, however, because they are conceptually similar to true RAID

applications.

RAID 1, RAID 10

In RAID 1 and RAID 10 virtual disks (commonly called

mirrored

virtual disks),

disk drives are paired, with both disk drives in a pair containing the same data.

When data is written to a mirrored virtual disk, it is written twice—once to each

disk drive in the pair. A RAID 1 virtual disk has only one set of paired disk drives.

A RAID 10 virtual disk has multiple pairs, across which data is striped.

The read performance of RAID 1 virtual disks can be much better than that of a

single disk drive, while the write performance is slightly lower. In RAID 10 virtual

disks, both read performance and write performance are better than those of a single

disk drive.