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Cache Read Prefetch, Additional Information

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Parameter owner cacheReadPrefetch segmentSize usageHint enclosureLossProtect drawerLossProtect securityType Description NOTE: A space must be added between the last digit and the size (bytes, KB, MB, or GB) for values greater than 9. If you do not specify a capacity, all the available physical disk capacity in the disk group is used. If you do not specify the capacity unit, bytes is used as the default unit. The setting for which RAID controller module owns the disk group. Valid RAID controller module identifier values are 0 and 1. The identifier value is 0 for the RAID controller module on the top and 1 for the RAID controller module on the bottom when viewed from the rear of the enclosure. If you do not specify an owner, the RAID controller module firmware determines the owner. The setting to turn on or turn off cache read prefetch. To turn off cache read prefetch, set this parameter to FALSE. To turn on cache read prefetch, set this parameter to TRUE. The amount of data (in KB) that the RAID controller module writes on a single physical disk in a virtual disk before writing data on the next physical disk. Valid values are 8, 16, 32, 64, 128, 256, or 512. The setting for both the cacheReadPrefetch parameter and the segmentSize parameter to be default values. The default values are based on the typical I/O usage pattern of the application that is using the virtual disk. Valid values are fileSystem, dataBase, or multiMedia. The setting to enforce enclosure loss protection when you create the disk group. To enforce enclosure loss protection, set this parameter to TRUE. The default value is FALSE. The setting to enforce drawer loss protection when you create the disk group. To enforce drawer loss protection, set this parameter to TRUE. The default value is FALSE. The setting to specify the security level when creating the disk groups and all associated virtual disks. • none-The disk group and virtual disks are not secure. • capable-The disk group and virtual disks are capable of having security set, but security has not been enabled. • enabled-The disk group and virtual disks have security enabled. Additional Information Cache Read Prefetch The cacheReadPrefetch command lets the RAID controller module copy additional data blocks into cache while the RAID controller module reads and copies data blocks that are requested by the host from the physical disks into cache. This action increases the chance that a future request for data can be fulfilled from cache. Cache read prefetch is important for multimedia applications that use sequential data transfers. The configuration settings for the storage array that you use determine the number of additional data blocks that the RAID controller module reads into cache. Valid values for the cacheReadPrefetch parameter are TRUE or FALSE. 107

Section	Page
Dell PowerVault Modular Disk Storage Arrays CLI Guide	3
About The Command Line Interface	11
How To Use The Command Line Interface	11
Usage Notes	12
CLI Commands	12
Command Line Parameters	14
Formatting Considerations	18
Detailed Error Reporting	18
Exit Status	19
Usage Examples	20
About The Script Commands	23
Script Command Structure	23
Script Command Synopsis	25
Recurring Syntax Elements	26
Usage Guidelines	30
Adding Comments To A Script File	30
Configuring A Storage Array	33
Configuring A Storage Array	33
Determining What Is On Your Storage Array	34
Saving A Configuration To A File	35
Using The Create Virtual Disk Command	36
Using The Auto Configure Command	38
Modifying Your Configuration	40
Setting The Storage Array Password	40
Setting Up SMTP And SNMP Alerts	40
Setting The RAID Controller Module Clocks	41
Setting The Storage Array Host Type	41
Setting Modification Priority	42
Assigning Global Hot Spares	42
Selecting The Event Levels For Alert Notifications	43
Configuring Alert Notifications	43
Using The Snapshot Feature	45
Using Host Servers To Create An Initial Snapshot Virtual Disk	46
Creating A Snapshot Virtual Disk	46
Enabling The Snapshot Virtual Disk Feature	47
Creating A Snapshot Virtual Disk With User-Assigned Physical Disks	47
Preparing Host Servers To Create An Initial Snapshot Virtual Disk	47
Creating The Initial Snapshot Virtual Disk	48
Creating A Snapshot Virtual Disk With Software-Assigned Physical Disks	49
Creating A Snapshot Virtual Disk By Specifying A Number Of Physical Disks	49
User-Defined Parameters	50
Names Of Snapshot Virtual Disks And Repository Virtual Disks	52
Changing Snapshot Virtual Disk Settings	53
Stopping And Deleting A Snapshot Virtual Disk	53
Re-creating The Snapshot Virtual Disk	54
Preparing Host Servers To Re-create A Snapshot Virtual Disk	54
Re-creating A Snapshot Virtual Disk	54
Using The Virtual Disk Copy Feature	57
Creating A Virtual Disk Copy	58
Enabling The Virtual Disk Copy Feature	58
Determining Virtual Disk Copy Candidates	58
Creating A Virtual Disk Copy	58
Preparing Host Servers To Create A Virtual Disk Copy	59
Copying The Virtual Disk	59
Viewing Virtual Disk Copy Properties	60
Changing Virtual Disk Copy Settings	61
Recopying A Virtual Disk	62
Preparing Host Servers To Recopy A Virtual Disk	62
Recopying The Virtual Disk	62
Stopping A Virtual Disk Copy	63
Removing Copy Pairs	63
Interaction With Other Features	64
Storage Partitioning	64
Snapshot Virtual Disks	64
Using The Remote Replication Premium Feature	67
How Remote Replication Works	67
Replication Repository Virtual Disks	68
Replication Relationships	68
Data Replication	68
Link Interruptions Or Secondary Virtual Disk Errors	69
Resynchronization	69
Creating A Remote Replicated Pair	70
Performance Considerations	70
Enabling The Remote Replication Premium Feature	71
Activating The Remote Replication Premium Feature	71
Determining Candidates For A Remote Replicated Pair	73
Creating A Remote Replicated Pair	73
Changing Remote Replication Settings	74
Suspending And Resuming A Replication Relationship	75
Removing A Replication Relationship	75
Deleting A Primary Virtual Disk Or A Secondary Virtual Disk	76
Disabling The Remote Replication Premium Feature	76
Deactivating The Remote Replication Premium Feature	76
Interaction With Other Premium Features	76
Snapshot Virtual Disks	77
Virtual Disk Copy	77
Storage Partitioning	77
Virtual Disk Expansion	78
Maintaining A Storage Array	79
Routine Maintenance	79
Running A Media Scan	79
Running A Consistency Check	80
Resetting A RAID Controller Module	80
Enabling RAID Controller Module Data Transfer	81
Resetting Battery Age	81
Removing Persistent Reservations	81
Synchronizing RAID Controller Module Clocks	81
Locating Physical Disks	81
Performance Tuning	82
Monitoring Performance	82
Changing RAID Levels	83
Changing Segment Size	83
Defragmenting A Disk Group	83
Troubleshooting and Diagnostics	83
Collecting Physical Disk Data	84
Diagnosing A RAID Controller Module	84
Recovery Operations	84
Setting RAID Controller Module Operational Mode	85
Changing RAID Controller Module Ownership	85
Initializing A Physical Disk	85
Reconstructing A Physical Disk	86
Initializing A Virtual Disk	86
Redistributing Virtual Disks	86
Script Commands	89
Command Formatting Rules	89
Firmware Compatibility Levels	91
Commands Listed By Function	91
Disk Group Commands	91
Enclosure Commands	91
Host Topology Commands	91
iSCSI Commands	92
Physical Disk Commands	92
RAID Controller Module Commands	93
Remote Replication Commands	93
Session Command	94
Show String Command	94
Snapshot Commands	94
Storage Array Commands	94
Virtual Disk Commands	95
Virtual Disk Copy Commands	96
Commands Listed Alphabetically	96
Activate Remote Replication Feature	96
Activate Storage Array Firmware	99
Autoconfigure Storage Array	99
Autoconfigure Storage Array Hot Spares	100
Check Remote Replication Status	100
Check Virtual Disk Consistency	101
Clear Physical Disk Port Statistics	102
Clear Storage Array Configuration	102
Clear Storage Array Core Dump	103
Clear Storage Array Event Log	103
Clear Storage Array Firmware Pending Area	103
Clear Storage Array Recovery Mode	104
Clear Virtual Disk Reservations	104
Clear Virtual Disk Unreadable Sectors	104
Configure Automatic Support Bundle Collection	105
Create Disk Group	105
Create Disk Pool	109
Create Host	111
Create Host Group	111
Create Host Port	111
Create iSCSI Initiator	112
Create RAID Virtual Disk (Automatic Physical Disk Select)	113
Create RAID Virtual Disk (Free Capacity Base Select)	114
Create RAID Virtual Disk (Manual Physical Disk Select)	116
Create RAID Virtual Disk On A Disk Pool	119
Create Remote Replication	120
Create Snapshot Virtual Disk	122
Scheduling Snapshots	126
Create Storage Array Security Key	127
Create Virtual Disk Copy	129
Deactivate Remote Replication	130
Delete Disk Group	130
Delete Disk Pool	131
Delete Host	131
Delete Host Group	131
Delete Host Port	132
Delete iSCSI Initiator	132
Delete Snapshot Virtual Disk or Delete Snapshot Virtual Disk Schedule	133
Delete Virtual Disk	133
Delete Virtual Disk On A Disk Pool	134
Diagnose RAID Controller Module	135
Diagnose RAID Controller Module iSCSI Host Cable	136
Diagnose Remote Replication	137
Disable Storage Array Feature	138
Display Automatic Support Bundle Collection Configuration	138
Display Support Bundle Collection Schedule	138
Download Enclosure Management Module Firmware	139
Download Physical Disk Firmware	139
Download Storage Array Firmware/NVSRAM	140
Download Storage Array Physical Disk Firmware	141
Download Storage Array NVSRAM	142
Enable Disk Group Security	142
Enable Disk Pool Security	142
Enable RAID Controller Module Data Transfer	143
Enable Storage Array Feature	143
Increase Virtual Disk Capacity On A Disk Pool	144
Load Storage Array DBM Database	144
Recopy Virtual Disk Copy	145
Re-Create Remote Replication Repository Virtual Disk	146
Re-Create Snapshot	148
Reduce Disk Pool Capacity	150
Remove Remote Replication	150
Remove Virtual Disk Copy	151
Remove Virtual Disk LUN Mapping	151
Repair Virtual Disk Consistency	152
Replace Physical Disk	152
Reset RAID Controller Module	153
Reset Storage Array Battery Install Date	154
Reset Storage Array iSCSI Baseline	154
Reset Storage Array SAS PHY Baseline	155
Reset Storage Array Virtual Disk Distribution	155
Resume Remote Replication	155
Resume Snapshot Rollback	156
Revive Disk Group	156
Revive Disk Pool	157
Revive Physical Disk	157
Save Enclosure Log Data	157
Save Physical Disk Channel Fault Isolation Diagnostic Status	158
Save Physical Disk Log	158
Save RAID Controller Module NVSRAM	158
Save Storage Array Configuration	159
Save Storage Array Events	160
Save Storage Array iSCSI Statistics	161
Save Storage Array Performance Statistics	161
Save Storage Array SAS PHY Counts	162
Save Storage Array State Capture	162
Save Storage Array Support Data	162
Schedule Support Bundle Collection Configuration	163
Scheduling Snapshots	164
Set Disk Group	165
Set Disk Group Forced State	167
Set Disk Pool	167
Set Enclosure Attribute	168
Set Enclosure Identification	168
Set Foreign Physical Disk to Native	169
Set Host	169
Set Host Channel	170
Set Host Group	171
Set Host Port	171
Set iSCSI Initiator	172
Set iSCSI Target Properties	172
Set Physical Disk Channel Status	173
Set Physical Disk Hot Spare	174
Set Physical Disk State	174
Set RAID Controller Module	175
Set Remote Replication	177
Set Session	179
Set Snapshot Virtual Disk	180
Set Storage Array	181
Set Storage Array Enclosure Positions	183
Set Storage Array ICMP Response	184
Set Storage Array iSNS Server IPv4 Address	184
Set Storage Array iSNS Server IPv6 Address	185
Set Storage Array iSNS Server Listening Port	185
Set Storage Array Learn Cycle	185
Set Storage Array Redundancy Mode	186
Set Storage Array Security Key	186
Set Storage Array Time	187
Set Storage Array Unnamed Discovery Session	187
Set Virtual Disk	187
Set Virtual Disk Copy	190
Show Current iSCSI Sessions	191
Show Disk Group	192
Show Disk Group Export Dependencies	192
Show Disk Group Import Dependencies	193
Show Disk Pool	193
Show Host Ports	193
Show Physical Disk	194
Show Physical Disk Channel Statistics	195
Show Physical Disk Download Progress	196
Show RAID Controller Module	196
Show RAID Controller Module NVSRAM	197
Show Remote Replication Virtual Disk Candidates	198
Show Remote Replication Virtual Disk Synchronization Progress	198
Show Storage Array	199
Show Storage Array Auto Configure	200
Show Storage Array Host Topology	201
Show Storage Array LUN Mappings	202
Show Storage Array Negotiation Defaults	202
Show Storage Array Unconfigured iSCSI Initiators	202
Show Storage Array Unreadable Sectors	203
Show String	203
Show Virtual Disk	203
Show Virtual Disk Action Progress	205
Show Virtual Disk Copy	205
Show Virtual Disk Copy Source Candidates	206
Show Virtual Disk Copy Target Candidates	206
Show Virtual Disk Performance Statistics	206
Show Virtual Disk Reservations	207
Start Configuration Database Diagnostic	207
Start Disk Group Blink	208
Start Disk Group Defragment	208
Start Disk Group Export	208
Start Disk Group Import	209
Start Disk Pool Locate	209
Start Enclosure Blink	209
Start iSCSI DHCP Refresh	210
Start Physical Disk Blink	210
Start Physical Disk Channel Blink	211
Start Physical Disk Channel Fault Isolation Diagnostics	211
Start Physical Disk Initialize	212
Start Physical Disk Reconstruction	212
Start Remote Replication Synchronization	213
Start Secure Physical Disk Erase	213
Start Snapshot Rollback	213
Stop Snapshot Rollback	214
Start Storage Array Blink	214
Start Storage Array iSCSI Refresh	214
Start Virtual Disk Initialization	215
Stop Configuration Database Diagnostic	215
Stop Disk Group Blink	215
Stop Disk Pool Locate	216
Stop Enclosure Blink	216
Stop Physical Disk Blink	216
Stop Physical Disk Channel Blink	216
Stop Physical Disk Channel Fault Isolation Diagnostics	216
Stop Snapshot	217
Stop Storage Array Blink	217
Stop Storage Array iSCSI Session	217
Stop Storage Array Physical Disk Firmware Download	217
Stop Virtual Disk Copy	218
Suspend Remote Replication	218
Validate Storage Array Security Key	219
Sample Script Files	221
Configuration Script Example 1	221
Configuration Script Example 2	222
CLI Command Updates	225
New Commands	225

Match case Limit results 1 per page

Parameter

Description

NOTE:

A space must be added between the last digit and the size

(bytes, KB, MB, or GB) for values greater than 9. If you do not specify

a capacity, all the available physical disk capacity in the disk group is

used. If you do not specify the capacity unit, bytes is used as the

default unit.

owner

The setting for which RAID controller module owns the disk group. Valid

RAID controller module identifier values are

and

. The identifier value is

for the RAID controller module on the top and

for the RAID controller

module on the bottom when viewed from the rear of the enclosure. If you

do not specify an owner, the RAID controller module firmware determines

the owner.

cacheReadPrefetch

The setting to turn on or turn off cache read prefetch. To turn off cache

read prefetch, set this parameter to

FALSE

. To turn on cache read

prefetch, set this parameter to

TRUE

segmentSize

The amount of data (in KB) that the RAID controller module writes on a

single physical disk in a virtual disk before writing data on the next

physical disk. Valid values are

128

256

, or

512

usageHint

The setting for both the

cacheReadPrefetch

parameter and the

segmentSize

parameter to be default values. The default values are

based on the typical I/O usage pattern of the application that is using the

virtual disk. Valid values are

fileSystem

dataBase

, or

multiMedia

enclosureLossProtect

The setting to enforce enclosure loss protection when you create the disk

group. To enforce enclosure loss protection, set this parameter to

TRUE

The default value is

FALSE

drawerLossProtect

The setting to enforce drawer loss protection when you create the disk

group. To enforce drawer loss protection, set this parameter to

TRUE

. The

default value is

FALSE

securityType

The setting to specify the security level when creating the disk groups and

all associated virtual disks.

•

none

—The disk group and virtual disks are not secure.

•

capable

—The disk group and virtual disks are capable of

having security set, but security has not been enabled.

•

enabled

—The disk group and virtual disks have security

enabled.

Additional Information

Cache Read Prefetch

The

cacheReadPrefetch

command lets the RAID controller module copy additional data blocks into cache while

the RAID controller module reads and copies data blocks that are requested by the host from the physical disks into

cache. This action increases the chance that a future request for data can be fulfilled from cache.

Cache read

prefetch

is important for multimedia applications that use sequential data transfers. The configuration settings for

the storage array that you use determine the number of additional data blocks that the RAID controller module reads into

cache. Valid values for the

cacheReadPrefetch

parameter are

TRUE

FALSE

107