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Maximizing Fault Tolerance, Table 2.13, RAID Levels and Fault Tolerance

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maximize virtual drive availability (fault tolerance), virtual drive performance, and virtual drive capacity. 2.6.1 Maximizing Fault Tolerance Fault tolerance is achieved through the ability to perform automatic and transparent rebuilds using hot spare drives and hot swaps. A hot spare drive is an unused online available drive that the RAID controller instantly plugs into the system when an active drive fails. After the hot spare is automatically moved into the RAID drive group, the failed drive is automatically rebuilt on the spare drive. The RAID drive group continues to handle requests while the rebuild occurs. A hot swap is the manual substitution of a replacement unit in a disk subsystem for a defective one, where the substitution can be performed while the subsystem is runninghot swap drives. Auto-Rebuild in the WebBIOS Configuration Utility allows a failed drive to be replaced and automatically rebuilt by "hot-swapping" the drive in the same drive bay. The RAID drive group continues to handle requests while the rebuild occurs, providing a high degree of fault tolerance and zero downtime. Table 2.13 RAID Levels and Fault Tolerance RAID Level Fault Tolerance 0 Does not provide fault tolerance. All data is lost if any drive fails. Disk striping writes data across multiple drives instead of just one drive. It involves partitioning each drive storage space into stripes that can vary in size. RAID 0 is ideal for applications that require high bandwidth but do not require fault tolerance. 1 Provides complete data redundancy. If one drive fails, the contents of the other drive in the drive group can be used to run the system and reconstruct the failed drive. The primary advantage of disk mirroring is that it provides 100 percent data redundancy. Since the contents of the drive are completely written to a second drive, no data is lost if one of the drives fails. Both drives contain the same data at all times. RAID 1 is ideal for any application that requires fault tolerance and minimal capacity. 5 Combines distributed parity with disk striping. Parity provides redundancy for one drive failure without duplicating the contents of entire drives. If a drive fails, the RAID controller uses the parity data to reconstruct all missing information. In RAID 5, this method is applied to entire drives or stripes across all drives in a drive group. Using distributed partiy, RAID 5 offers fault tolerance with limited overhead. 2-28 Introduction to RAID

Section	Page
Title Page	1
Copyright Notice	4
Preface	5
Contents	7
Chapter 1: Overview	25
1.1 SAS Technology	25
1.2 Serial-attached SCSI Device Interface	27
1.3 Serial ATA II Features	27
1.4 Solid State Drive Features	28
1.4.1 Solid State Drive Guard	28
1.5 Dimmer Switch Feature	29
1.6 UEFI 2.0 Support	29
1.7 Configuration Scenarios	30
1.7.1 Valid Drive Mix Configurations with HDDs and SSDs	32
Chapter 2: Introduction to RAID	33
2.1 RAID Description	33
2.2 RAID Benefits	33
2.3 RAID Functions	33
2.4 Components and Features	34
2.4.1 Physical Array	34
2.4.2 Virtual Drive	34
2.4.3 RAID Drive Group	35
2.4.4 Fault Tolerance	35
2.4.5 Consistency Check	37
2.4.6 Copyback	37
2.4.7 Background Initialization	38
2.4.8 Patrol Read	39
2.4.9 Disk Striping	39
2.4.10 Disk Mirroring	40
2.4.11 Parity	41
2.4.12 Disk Spanning	42
2.4.13 Hot Spares	43
2.4.14 Disk Rebuilds	45
2.4.15 Rebuild Rate	46
2.4.16 Hot Swap	46
2.4.17 Drive States	46
2.4.18 Virtual Drive States	47
2.4.19 Enclosure Management	48
2.5 RAID Levels	48
2.5.1 Summary of RAID Levels	48
2.5.2 Selecting a RAID Level	49
2.5.3 RAID 0	50
2.5.4 RAID 1	51
2.5.5 RAID 5	51
2.5.6 RAID 6	53
2.5.7 RAID 00	54
2.5.8 RAID 10	55
2.5.9 RAID 50	56
2.5.10 RAID 60	58
2.6 RAID Configuration Strategies	59
2.6.1 Maximizing Fault Tolerance	60
2.6.2 Maximizing Performance	61
2.6.3 Maximizing Storage Capacity	63
2.7 RAID Availability	64
2.7.1 RAID Availability Concept	64
2.8 Configuration Planning	65
2.8.1 Number of Drives	66
2.8.2 Drive Group Purpose	66
Chapter 3: Full Disk Encryption	69
3.1 Overview	69
3.2 Purpose	70
3.3 Terminology	70
3.4 Workflow	71
3.4.1 Enable Security	71
3.4.2 Change Security	72
3.4.3 Create Secure Virtual Drives	73
3.4.4 Import a Foreign Configuration	74
3.5 Instant Secure Erase	75
Chapter 4: WebBIOS Configuration Utility	77
4.1 Overview	77
4.2 Starting the WebBIOS CU	78
4.3 WebBIOS CU Main Screen Options	79
4.4 Creating a Storage Configuration	81
4.4.1 Selecting the Configuration with the Configuration Wizard	82
4.4.2 Using Automatic Configuration	84
4.4.3 Using Manual Configuration	85
4.5 Selecting Full Disk Encryption Security Options	134
4.5.1 Enabling the Security Key Identifier, Security Key, and Passphrase	135
4.5.2 Changing the Security Key Identifier, Security Key, and Pass Phrase	140
4.5.3 Disabling the Drive Security Settings	147
4.5.4 Importing Foreign Configurations	149
4.6 Viewing and Changing Device Properties	150
4.6.1 Viewing and Changing Controller Properties	150
4.6.2 Viewing and Changing Virtual Drive Properties	154
4.6.3 Viewing Drive Properties	156
4.6.4 Viewing and Changing Battery Backup Unit Information	158
4.7 Viewing System Event Information	161
4.8 Managing Configurations	163
4.8.1 Running a Consistency Check	163
4.8.2 Deleting a Virtual Drive	164
4.8.3 Importing or Clearing a Foreign Configuration	164
4.8.4 Migrating the RAID Level of a Virtual Drive	168
Chapter 5: MegaRAID Command Tool	171
5.1 Product Overview	172
5.2 Novell NetWare, SCO, Solaris, FreeBSD, and DOS Operating System Support	174
5.3 Command Line Abbreviations and Conventions	174
5.3.1 Abbreviations Used in the Command Line	174
5.3.2 Conventions	175
5.4 Controller Property-Related Options	176
5.4.1 Display Controller Properties	176
5.4.2 Display Number of Controllers Supported	177
5.4.3 Enable or Disable Automatic Rebuild	177
5.4.4 Flush Controller Cache	177
5.4.5 Set Controller Properties	178
5.4.6 Display Specified Controller Properties	179
5.4.7 Set Factory Defaults	180
5.4.8 Set SAS Address	180
5.4.9 Set Time and Date on Controller	180
5.4.10 Display Time and Date on Controller	181
5.5 Patrol Read-Related Controller Properties	181
5.5.1 Set Patrol Read Options	181
5.5.2 Set Patrol Read Delay Interval	182
5.6 BIOS-Related Properties	182
5.6.1 Set or Display Bootable Virtual Drive ID	183
5.6.2 Select BIOS Status Options	183
5.7 Battery Backup Unit-Related Properties	183
5.7.1 Display BBU Information	184
5.7.2 Display BBU Status Information	184
5.7.3 Display BBU Capacity	185
5.7.4 Display BBU Design Parameters	186
5.7.5 Display Current BBU Properties	186
5.7.6 Start BBU Learning Cycle	187
5.7.7 Place Battery in Low-Power Storage Mode	187
5.7.8 Set BBU Properties	187
5.8 Options for Displaying Logs Kept at Firmware Level	188
5.8.1 Event Log Management	188
5.8.2 Set BBU Terminal Logging	189
5.9 Configuration-Related Options	189
5.9.1 Create a RAID Drive Group from All Unconfigured Good Drives	190
5.9.2 Add RAID 0, 1, 5, or 6 Configuration	191
5.9.3 Add RAID 10, 50, or 60 Configuration	193
5.9.4 Clear the Existing Configuration	193
5.9.5 Save the Configuration on the Controller	194
5.9.6 Restore the Configuration Data from File	194
5.9.7 Manage Foreign Configuration Information	194
5.9.8 Delete Specified Virtual Drive(s)	195
5.9.9 Display the Free Space	195
5.10 Virtual Drive-Related Options	196
5.10.1 Display Virtual Drive Information	196
5.10.2 Change the Virtual Drive Cache and Access Parameters	196
5.10.3 Display the Virtual Drive Cache and Access Parameters	197
5.10.4 Manage Virtual Drives Initialization	197
5.10.5 Manage a Consistency Check	198
5.10.6 Manage a Background Initialization	198
5.10.7 Perform a Virtual Drive Reconstruction	199
5.10.8 Display Information about Virtual Drives and Drives	199
5.10.9 Display the Number of Virtual Drives	199
5.11 Drive-Related Options	200
5.11.1 Display Drive Information	200
5.11.2 Set the Drive State to Online	200
5.11.3 Set the Drive State to Offline	200
5.11.4 Change the Drive State to Unconfigured Good	201
5.11.5 Change Drive State	201
5.11.6 Manage a Drive Initialization	202
5.11.7 Rebuild a Drive	202
5.11.8 Locate the Drive(s) and Activate LED	203
5.11.9 Mark the Configured Drive as Missing	203
5.11.10 Display the Drives in Missing Status	203
5.11.11 Replace the Configured Drives and Start an Automatic Rebuild	203
5.11.12 Prepare the Unconfigured Drive for Removal	204
5.11.13 Display Total Number of Drives	204
5.11.14 Display List of Physical Devices	204
5.11.15 Download Firmware to the Physical Devices	205
5.12 Enclosure-Related Options	205
5.13 Flashing the Firmware	205
5.13.1 Flash the Firmware with the ROM File	205
5.13.2 Flash the Firmware in Mode 0 with the ROM File	206
5.14 SAS Topology	206
5.15 Diagnostic-Related Options	207
5.15.1 Start Controller Diagnostics	207
5.15.2 Start Battery Test	207
5.15.3 Start NVRAM Diagnostic	207
5.16 Miscellaneous Options	208
5.16.1 Display the MegaCLI Version	208
5.16.2 Display Help for MegaCLI	208
Chapter 6: MegaRAID Storage Manager Overview and Installation	209
6.1 Overview	209
6.1.1 Creating Storage Configurations	209
6.1.2 Monitoring Storage Devices	210
6.1.3 Maintaining Storage Configurations	210
6.2 Hardware and Software Requirements	210
6.3 Installing MegaRAID Storage Manager	211
6.3.1 Installing MegaRAID Storage Manager Software on Microsoft Windows	211
6.3.2 Installing MegaRAID Storage Manager Software for Linux	216
6.3.3 Linux Error Messages	217
6.4 MegaRAID Storage Manager Support and Installation on VMWare	218
6.4.1 Installing MegaRAID Storage Manager for VMWare Classic	218
6.4.2 Uninstalling MegaRAID Storage Manager for VMWare	219
6.4.3 Installing MegaRAID Storage Manager Support on the VMWare ESX Operating System	219
6.5 Installing and Configuring a CIM Provider	231
6.5.1 Installing a CIM SAS Storage Provider on Linux	231
6.5.2 Installing a CIM SAS Storage Provider on Windows	233
6.6 Installing and Configuring an SNMP Agent	233
6.6.1 Installing and Configuring an SNMP Agent on Linux	234
6.6.2 Installing and Configuring an SNMP Agent on Solaris	236
6.6.3 Installing an SNMP Agent on Windows	240
6.7 MegaRAID Storage Manager Support and Installation on Solaris 10	241
6.7.1 Installing MegaRAID Storage Manager Software for Solaris 10	241
6.7.2 Uninstalling MegaRAID Storage Manager Software for Solaris 10	242
Chapter 7: MegaRAID Storage Manager Window and Menus	243
7.1 Starting MegaRAID Storage Manager Software	243
7.2 MegaRAID Storage Manager Window	246
7.2.1 Physical/Logical View Panel	247
7.2.2 Properties/Operations Panels	248
7.2.3 Event Log Panel	249
7.2.4 Menu Bar	250
Chapter 8: Configuration	253
8.1 Creating a New Storage Configuration	254
8.1.1 Selecting Virtual Drive Settings	254
8.1.2 Creating a Virtual Drive Using Simple Configuration	256
8.1.3 Creating a Virtual Drive Using Advanced Configuration	261
8.2 Selecting Full Disk Encryption Security Options	270
8.2.1 Enabling Drive Security	270
8.2.2 Changing the Security Key Identifier, Security Key, and Pass Phrase	276
8.2.3 Disabling Drive Security	282
8.2.4 Importing or Clearing a Foreign Configuration	284
8.3 Adding Hot Spare Drives	287
8.4 Changing Adjustable Task Rates	289
8.5 Changing Power Settings	291
8.6 Changing Virtual Drive Properties	292
8.7 Changing a Virtual Drive Configuration	293
8.7.1 Accessing the Modify Drive Group Wizard	293
8.7.2 Adding a Drive or Drives to a Configuration	295
8.7.3 Removing a Drive from a Configuration	296
8.7.4 Changing the RAID Level of a Virtual Drive	297
8.8 Deleting a Virtual Drive	297
8.9 Saving a Storage Configuration to Drive	298
8.10 Clearing a Storage Configuration from a Controller	298
8.11 Adding a Saved Storage Configuration	299
Chapter 9: Monitoring System Events and Storage Devices	301
9.1 Monitoring System Events	301
9.2 Configuring Alert Notifications	303
9.2.1 Setting Alert Delivery Methods	305
9.2.2 Changing Alert Delivery Methods for Individual Events	306
9.2.3 Changing the Severity Level for Individual Events	307
9.2.4 Entering or Editing the Sender Email Address and SMTP Server	309
9.2.5 Authenticating a Server	310
9.2.6 Saving Backup Configurations	310
9.2.7 Loading Backup Configurations	310
9.2.8 Adding Email Addresses of Recipients of Alert Notifications	311
9.2.9 Testing Email Addresses of Recipients of Alert Notifications	312
9.2.10 Removing Email Addresses of Recipients of Alert Notifications	313
9.3 Monitoring Controllers	313
9.4 Monitoring Drives	315
9.5 Running a Patrol Read	316
9.6 Monitoring Virtual Drives	319
9.7 Monitoring Enclosures	321
9.8 Monitoring Battery Backup Units	322
9.8.1 Battery Learn Cycle	324
9.9 Monitoring Rebuilds and Other Processes	326
Chapter 10: Maintaining and Managing Storage Configurations	329
10.1 Initializing a Virtual Drive	329
10.2 Running a Consistency Check	330
10.3 Scanning for New Drives	331
10.4 Rebuilding a Drive	331
10.5 Making a Drive Offline or Missing	332
10.6 Upgrading the Firmware	333
Appendix A: Events and Messages	335
Appendix B: Glossary	349

Match case Limit results 1 per page

2-28

Introduction to RAID

maximize virtual drive availability (fault tolerance), virtual drive

performance, and virtual drive capacity.

2.6.1

Maximizing Fault Tolerance

Fault tolerance is achieved through the ability to perform automatic and

transparent rebuilds using hot spare drives and hot swaps. A hot spare

drive is an unused online available drive that the RAID controller instantly

plugs into the system when an active drive fails. After the hot spare is

automatically moved into the RAID drive group, the failed drive is

automatically rebuilt on the spare drive. The RAID drive group continues

to handle requests while the rebuild occurs.

A hot swap is the manual substitution of a replacement unit in a disk

subsystem for a defective one, where the substitution can be performed

while the subsystem is runninghot swap drives. Auto-Rebuild in the

WebBIOS Configuration Utility allows a failed drive to be replaced and

automatically rebuilt by “hot-swapping” the drive in the same drive bay.

The RAID drive group continues to handle requests while the rebuild

occurs, providing a high degree of fault tolerance and zero downtime.

Table 2.13

RAID Levels and Fault Tolerance

RAID

Level

Fault Tolerance

Does not provide fault tolerance. All data is lost if any drive fails. Disk striping writes

data across multiple drives instead of just one drive. It involves partitioning each drive

storage space into stripes that can vary in size. RAID 0 is ideal for applications that

require high bandwidth but do not require fault tolerance.

Provides complete data redundancy. If one drive fails, the contents of the other drive in

the drive group can be used to run the system and reconstruct the failed drive.

The primary advantage of disk mirroring is that it provides 100 percent data

redundancy. Since the contents of the drive are completely written to a second drive,

no data is lost if one of the drives fails. Both drives contain the same data at all times.

RAID 1 is ideal for any application that requires fault tolerance and minimal capacity.

Combines distributed parity with disk striping. Parity provides redundancy for one drive

failure without duplicating the contents of entire drives. If a drive fails, the RAID

controller uses the parity data to reconstruct all missing information. In RAID 5, this

method is applied to entire drives or stripes across all drives in a drive group. Using

distributed partiy, RAID 5 offers fault tolerance with limited overhead.