If Using PERC 2/DC BIOS Configuration Utility Table 2. BIOS Configuration Utility Functions and Corresponding Menus
For information about other functions, see the following menu tree and menu descriptions.
PERC 2/DC BIOS Configuration Utility Menu TreeThe following is an expansion of the menus in the PERC 2/DC BIOS Configuration Utility. Figure 1. PERC 2/DC BIOS Configuration Utility Menu Tree 
PERC 2/DC Configuration On DiskPERC 2/DC supports Configuration on Disk (drive roaming). Configuration on Disk saves configuration information both in the PERC 2/DC NVRAM and on the disk drives attached to PERC 2/DC. If PERC 2/DC is replaced, the new PERC 2/DC controller can detect the RAID configuration, maintaining the integrity of the data on each drive even if the drives have changed target ID.
Adding Configuration on Disk Support Perform the following steps: 1. Press <Ctrl> <M> at the PERC 2/DC POST screen to run the PERC 2/DC BIOS Configuration Utility. 2. Select the Configure Menu. Select View/Add Configuration. Select Disk when asked to use Disk or NVRAM and select Save. 3. Press <Esc> to exit PERC 2/DC BIOS Configuration Utility. 4. Reboot the computer.
BIOS Configuration Utility Configure Menu
Configure Choose the Configure option to select a method for configuring arrays and logical drives. Table 3. Configuration Options for Arrays and Logical Drives
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Warning Initializing a logical drive destroys all data on the logical drive. |
Objects
Choose the Objects option from the BIOS Configuration Utility main menu to access the controllers, logical drives, physical drives, and SCSI channels individually. You can also change settings for each object. The Objects menu options are as follows:
Adapter
Choose Adapter from the Objects menu to select a controller (if the computer has more than one) and to modify parameters. You can install up to two PERC 2/DC controllers, and you can also install other PERC controllers.
The Adapter menu is shown below:
Menu Options
The Objects/Adapter menu options are:
Table 4. Objects\Adapter Menu Items
|
Option |
Description |
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Clear Configuration |
Choose this option to erase the current configuration from the controller non-volatile memory. |
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FlexRAID PowerFail |
Choose this option to enable the FlexRAID PowerFail feature. Choose this option to allow drive reconstruction to continue when the system restarts if a power failure occurs. |
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Disk Spin-Up Timings |
Choose this option to set the method and timing for spinning up the hard disk drives. |
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Cache Flush Timings |
Choose this option to set the cache flush interval to once every 2, 4, 6, 8, or 10 seconds. |
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Rebuild Rate |
Choose this option to display and change the rebuild rate for drives attached to the selected adapter. |
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Alarm Control |
Choose this option to enable, disable, or silence the onboard alarm tone generator. |
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Factory Defaults |
Choose this option to load the default PERC BIOS Configuration Utility settings. |
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Enable BIOS |
You can enable or disable the PERC 2/DC BIOS. Enable the BIOS when you work in standard mode. |
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Adapter Type |
PERC 2/DC appears. You cannot choose any other type. |
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Emulation |
You can operate in the I2O mode or mass storage mode. If you operate in mass storage mode, you need the Dell drivers. If you operate in the I2O mode, you can use either the Dell drivers or the drivers for your operating system, such as Windows NT, Novell, or UNIX. |
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SCSI Transfer rate |
The rate at which information is transferred to and from the disk drives. The options are Fast, Ultra, or Ultra 2. |
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Auto Rebuild |
Set to Enabled to automatically rebuild drives when they fail. |
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Initiator ID |
ID for the cluster card. It cannot have the same ID as the other node. |
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Cluster Mode |
You can enable or disable cluster mode. When you disable cluster mode, the system operates in standard mode. "Cluster:Adapter" or "Standard:Adapter" displays in the upper right corner of the screen. |
Cluster Mode and the Initiator ID
You can enable or disable cluster mode. When you disable cluster mode, the system operates in standard mode. In addition, when you enable cluster mode, the system automatically disables the BIOS.
You can change the Initiator ID only when you are in cluster mode. You cannot change the ID while in standard mode. The ID can be a number from 0 to 15. We recommend that you use 6 or 7. When you are in standard mode, the ID is always 7
Logical Drive
Choose this option from the BIOS Configuration Utility Objects menu to select a logical drive and perform the listed actions.
Table 5. Logical Drive Actions
|
Option |
Description |
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Initialize |
Initializes the selected logical drive. Do this for every logical drive that is configured. |
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Check Consistency |
Verifies the correctness of the redundancy data in the selected logical drive. This option is available only if RAID level 1 or 5 is used. PERC 2/DC automatically corrects any differences found in the data. |
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View/Update Parameters |
Displays the properties of the selected logical drive. You can modify the cache write policy, read policy, and the input/output (I/O) policy and can enable Virtual Sizing from this menu. |
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Important Dell recommends using the write-through cache policy. PERC 2/DC does not have battery-backed cache. Data may be lost because of a power failure or improper shutdown. In Cluster mode, PERC 2/DC allows write-through cache policy only. |
Virtual Sizing
Virtual Sizing allows PERC to determine the drive capacity. The operating system reports the drive capacity as determined by PERC. Virtual sizing is not supported in cluster mode.
Select Virtual Sizing from the View/Update Properties option on the Logical Drive menu. The Logical Drive menu is selected from the BIOS Configuration Utility Objects menu. Select Enabled to enable Virtual Sizing. Set this option to Enabled before adding a physical drive to a logical drive. After you have created a logical drive set, the partition of the drive should be as large as the virtual size of the logical drive. After you have created a logical array set, the drive partition can be as large as the full size of the logical drive. However, this is the full virtual drive size, not the actual physical drive size.
Physical Drive
Choose this option from the BIOS Configuration Utility Objects menu to select a physical device and to perform the operations listed in the table below. The physical hard disk drives in the computer are listed. Move the cursor to the desired device and press <Enter> to display the following:
You can perform the following operations on the selected physical hard disk drives.
Table 6. Physical Drive Actions
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Option |
Description |
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Rebuild |
Rebuilds the selected physical drive. |
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Format |
Low-level formats the selected disk drive. |
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Force Online |
Changes the state of the selected disk drive to Online. |
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Force Offline |
Change the state of the selected disk drive to Offline. |
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Make HotSpare |
Designates the selected disk drive as a hot spare. |
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View Drive Information |
Displays the drive properties for the selected physical device. |
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Synchronous Negotiation |
Enables or disables synchronous negotiation for the selected physical device. The default is Enabled. |
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SCSI-2 Command Tagging |
Sets the number of queue tags per command to Disabled, 2, 3, 4, or Enhanced. The default is Enhanced. |
SCSI Channel
Choose this option from the BIOS Configuration Utility Objects menu to select a SCSI channel on the currently selected controller. You can perform the following operation on the selected channel.
Table 7. SCSI Channel Option
|
Option |
Description |
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Termination Enabled/Disabled |
When set to Enabled, the PERC 2/DC controller is terminated. When set to Disabled, it is not. Normally, you will not need to change this setting. PERC 2/DC automatically sets this option. |
Battery Backup
Choose this option from the BIOS Configuration Utility Options menu to view the battery backup information, as shown below. You can use the battery backup menu to reset the charge cycle count.
The menu options are:
|
Menu Item |
Explanation |
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Backup Module |
PRESENT will appear if there is a battery module; ABSENT if there is not. |
| Battery Pack |
PRESENT will appear if the battery pack is properly installed; ABSENT if it is not. |
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Temperature |
GOOD appears if the temperature is within the normal range. HIGH appears if the module is too hot. |
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Voltage |
GOOD appears if the temperature is within the normal range. HIGH appears if the module is too hot. |
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Fast Charging |
COMPLETED appears if the fast charge cycle is done. CHARGING appears if the battery pack is charging. |
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No of Cycles |
This must be configured. When first installing a battery
pack, set the Charge Cycle to 0. The screen below appears when you select
No of Cycles. Choose YES to reset the number of cycles to zero and press
After 1100 charge cycles, the life of the battery
pack is assumed to be over and you must replace the battery pack.
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Format
Choose the Format option from the BIOS Configuration Utility main menu to low-level format one or more physical drives.
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Warning Formatting a hard drive destroys all data on the drive. |
Formatting
Since most SCSI disk drives are low-level formatted at the factory, this step is usually not necessary. You must format a disk only if:
- the disk drive was not low-level formatted at the factory, or
- an excessive number of media errors have been detected on the disk drive.
You do not have to choose Format to erase existing information on your SCSI disks, such as a system partition. That information is erased when you initialize the logical drive(s).
Rebuild
Choose the Rebuild option from the BIOS Configuration Utility main menu to rebuild one or more failed disk drives.
Check Consistency
Choose this option to verify the redundancy data in logical drives that use RAID levels 1, 5, 10 and 50.
The parameters of the existing logical drives appear. Discrepancies are automatically corrected, assuming always that the data is correct. However, if the failure is a read error on a data drive, the bad data block is reassigned with the generated data.
Press the arrow keys to choose the desired logical drives. Press the spacebar to select or deselect a drive for consistency checking. Press <F2> to select or deselect all the logical drives. Press <F10> to begin the consistency check. A
progress indicator for each selected logical drive displays, as shown below:
When the check is finished, press any key to clear the progress display. Press <Esc> to display the main menu. (To check an individual drive, select Objects on the main menu, then Logical Drives, the desired logical drive(s) and Check Consistency on the action menu to perform the Check Consistency action.)
You can configure physical arrays and logical drives with PERC 2/DC BIOS Configuration Utility using:
- Easy Configuration,
- New Configuration, or
- View/Add Configuration.
Each configuration method requires a different level of user input. The general flow of operations for array and logical drive configuration is:
1. Choose a configuration method.
2. Designate hot spares (optional).
3. Create arrays using the available physical drives.
4. Define logical drives using the space in the arrays.
5. Save the configuration information.
6. Initialize the new logical drives.
Easy Configuration
In Easy Configuration, each physical array you create is associated with exactly one logical drive, and you can modify the following parameters:
- RAID level,
- stripe size,
- cache write policy,
- Read policy, and
- I/O policy.
If logical drives have already been configured when you select Easy Configuration, the configuration information is not disturbed.
New Configuration
In New Configuration, you can modify the following logical drive parameters:
- RAID level,
- stripe size,
- cache write policy,
- Read policy,
- I/O policy,
- logical drive size, and
- spanning of arrays.
If you select New Configuration, the existing configuration information on the selected controller is destroyed when the new configuration is saved.
View/Add Configuration
View/Add Configuration allows you to control the same logical drive parameters as New Configuration without disturbing the existing configuration information. You can also choose to enable the Configuration on Disk feature.
PERC 2/DC Default Settings
Stripe Size - 64 KB
Write Policy - Write-back
Read-Ahead Policy - Adaptive
Cache Policy - Direct I/O
FlexRAID Virtual Sizing - OFF
FlexRAID PowerFail - ON (OFF for cluster enabled)
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In Cluster mode, PERC 2/DC allows write-through cache policy only. |
Reserved Disk Space during Configuration
Up to 20.6 MB of disk space is reserved when a hard disk drive is being configured.
Hot Spares
Hot spares are physical drives that are powered up along with the RAID drives and usually stay in a standby state. The hot spare drive should be larger than or equal to the smallest logical drive. If a disk drive used in a RAID logical drive fails, a hot spare will automatically take its place and the data on the failed drive is reconstructed on the hot spare. Hot spares can be used for RAID levels 1 and 5. Each PERC 2/DC controller supports up to eight hot spares.
The methods for designating physical drives as hot spares are:
- press <F4> while creating arrays in Easy, New or View/Add Configuration mode, or
- from the Objects/Physical Drive menu, select a physical drive and press <Enter.> Select Make HotSpare.
Press <F4>
When you choose any configuration option, a list of all physical devices connected to the current controller appears.
Press the arrow keys to choose a disk drive that has a READY indicator and press <F4> to designate the drive as a hot spare. The indicator will change to HOTSP.
Objects Menu
Select Objects from the Management menu, then select Physical Drive. A physical drive selection screen will appear. Select a disk drive and press <Enter> to display the action menu for the drive.
Press the arrow keys to select Make HotSpare and press <Enter>. The indicator for the selected drive changes to HOTSP.
In Easy Configuration, each array is associated with exactly one logical drive. Follow the steps below to create arrays using Easy Configuration. PERC 2/DC has two SCSI channels.
1. Choose Configure from the PERC 2/DC BIOS Configuration Utility main menu.
2. Choose Easy Configuration from the Configure menu. The array selection menu appears:
Hot key information is displayed at the bottom of the screen. The hot key functions are:
<F2> Display the manufacturer data and error count for the selected drive.
<F3> Display the logical drives that have been configured.
<F4> Designate the selected drive as a hot spare.
3. Press the arrow keys to choose specific physical drives. Press the spacebar to associate the selected physical drive with the current array. The indicator for the selected drive changes from READY to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means disk drive 3 in array 2.
Add physical drives to the current array as desired. Try to use drives of the same capacity in a specific array. If you use drives with different capacities in an array, all drives in the array are treated as if they have the capacity of the smallest drive in the array.
The number of physical drives in a specific array determine the RAID levels that can be implemented with the array.
RAID 0 requires one or more physical drives,
RAID 1 requires exactly two physical drives, and
RAID 5 requires at least three physical drives.
4. Press <Enter> when you are finished creating the current array. The logical drive configuration screen appears.
The window from the top of the screen shows the logical drive that is currently being configured as well as any existing logical drives.
The column headings are:
LD - The logical drive number,
RAID - The RAID level,
Size - The logical drive size,
#Stripes - The number of stripes (physical drives) in the associated physical array,
StrpSz - The stripe size, and
DriveState - The state of the logical drive.
5. Set the RAID level for the logical drive. Highlight RAID and press <Enter>. The available RAID levels for the current logical drive are displayed. Select a RAID level and press <Enter> to confirm. See Chapter 3 RAID Levels for an explanation of the RAID levels.
6. Set the stripe size, cache write policy, Read policy, and I/O (cache) policy from the Advanced Menu.
Stripe size This parameter specifies the size of the segments written to each disk in a RAID 1 or 5 logical drive. You can set the stripe size to 2 KB, 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or 128 KB. A larger stripe size produces better read performance, especially if your computer does mostly sequential reads. If you are sure that your computer does random read requests more often, choose a small stripe size. The default is 64 KB.
Write Policy This option sets the caching method to write-back or write-through.
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In Cluster mode, PERC 2/DC allows write-through cache policy only. |
In Write-back caching, the controller sends a data transfer completion signal to the host when the controller cache has received all the data in a transaction. This setting is recommended in standard mode.
In Write-through caching, the controller sends a data transfer completion signal to the host when the disk subsystem has received all the data in a transaction. This is the default setting if cluster mode is enabled.
Write-through caching has a data security advantage over write-back caching. Write-back caching has a performance advantage over write-through caching.
Read-ahead This option enables the SCSI read-ahead feature for the logical drive. You can set this parameter to No-Read-Ahead, Read-ahead, or Adaptive.
No-Read-Ahead specifies that the controller does not use read-ahead for the current logical drive.
Read-ahead specifies that the controller uses read-ahead for the current logical drive.
Adaptive specifies that the controller begins using read-ahead if the two most recent disk accesses occurred in sequential sectors. If all read requests are random, the algorithm reverts to No-Read-Ahead, however, all requests are still evaluated for possible sequential operation. This is the default setting.
Cache Policy This parameter applies to reads on a specific logical drive. It does not affect the Read ahead cache.
Cached I/O specifies that all reads are buffered in cache memory.
Direct I/O specifies that reads are not buffered in cache memory. Direct I/O does not override the cache policy settings. Data is transferred to cache and the host concurrently. If the same data block is read again, it comes from cache memory. This is the default setting.
Press <Esc> to exit the Advanced Menu.
When you have defined the current logical drive, choose Accept and press <Enter>. The array selection screen appears if any unconfigured disk drives remain.
Note: PERC 2/DC supports spanning
across RAID 1 and 5 arrays only.
8. Repeat steps 3 through 7 to configure another array and logical drive. PERC 2/DC supports up to eight logical drives per controller. If you are finished configuring logical drives, press <Esc> to exit Easy Configuration. A list of the currently configured logical drives appears:
After you respond to the Save prompt, the Configure menu appears.
9. Initialize the logical drives you have just configured.
The New Configuration option allows you to associate logical drives with multiple physical arrays (this is known as spanning of arrays).
Erases Configuration
Choosing the New Configuration option erases the existing configuration information on the selected controller.
To use the spanning feature and keep the existing configuration, use View/Add Configuration.
1. Choose Configure from the PERC 2/DC BIOS Configuration Utility main menu.
2. Choose New Configuration from the Configure menu. An array selection window displays, showing the devices connected to the current controller.
Hot key information appears at the bottom of the screen. The hot key functions are:
<F2> Display drive data and PERC 2/DC error count for the selected drive.
<F3> Display the logical drives that have been configured.
<F4> Designate the selected drive as a hot spare.
<F10> Display the logical drive configuration screen.
3. Press the arrow keys to choose specific physical drives. Press the spacebar to associate the selected physical drive with the current array. The indicator for the selected drive changes from READY to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means disk drive 3 in array 2.
Add physical drives to the current array as desired. Try to use drives of the same capacity in a specific array. If you use drives with different capacities in an array, all the drives in the array is treated as though they have the capacity of the smallest drive in the array.
The number of physical drives in a specific array determines the RAID levels that can be implemented with the array.
RAID 0 requires one or more physical drives per array.
RAID 1 requires two physical drives per array.
RAID 5 requires at least three physical drives per array.
RAID 10 requires at least four physical drives per array.
RAID 50 requires at least six physical drives per array.
4. Press <Enter> when you are finished creating the current array. To continue defining arrays, repeat step 3. To begin logical drive configuration, go to step 5.
5. Press <F10> to configure logical drives. The logical drive configuration screen appears, as shown below:
The window at the top of the screen shows the logical drive that is currently being configured as well as any existing logical drives.
The column headings are:
LD - The logical drive number,
RAID - The RAID level,
Size - The logical drive size,
#Stripes - The number of stripes (physical drives) in the associated physical array,
StrpSz - The stripe size, and
Drive-State - The state of the logical drive.
6. Set the RAID level for the logical drive. Highlight RAID and press <Enter>. A list of the available RAID levels for the current logical drive appears. Select a RAID level and press <Enter> to confirm. See Chapter 3 RAID Levels for an explanation of the RAID levels.
7. Set the spanning mode for the current logical drive. Highlight Span and press <Enter>. The choices are:
CanSpan Array spanning is enabled for the current logical drive. The logical drive can occupy space in more than one array.
NoSpan Array spanning is disabled for the current logical drive. The logical drive can occupy space in only one array.
PERC 2/DC supports spanning of RAID 1 and 5 arrays only. You can span two or more contiguous RAID 1 logical drives into a RAID 10 array, and two or more contiguous RAID 5 logical drives into a RAID 50 array.
For two arrays to be spannable, they must have the same stripe width (they must contain the same number of physical drives) and must be consecutively numbered. For example, assuming Array 2 contains four disk drives, it can be spanned only with Array 1 and/or Array 3, and only if Arrays 1 and 3 also contain four disk drives. If the two criteria for spanning are met, PERC 2/DC automatically allows spanning. If the criteria are not met, the Span setting makes no difference for the current logical drive. Highlight a spanning option and press <Enter>.
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PERC 2/DC supports spanning for RAID 1 and RAID 5 only. You can configure RAID 10 by spanning two or more contiguous RAID 1 logical drives. You can configure RAID 50 by spanning two or more contiguous RAID 5 logical drives. The logical drives must have the same stripe size. |
- Set the logical drive size. Move the cursor to Size and press <Enter>. By default, the logical drive size is set to all available space in the array(s) being associated with the current logical drive, accounting for the Span setting.
Open the Advanced menu to set the remaining options.
Stripe size This parameter specifies the size of the segments written to each disk in a RAID 1 or 5 logical drive. You can set the stripe size to 2 KB, 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or 128 KB. A larger stripe size produces higher read performance, especially if your computer does mostly sequential reads. However, if you are sure that your computer does random read requests more often, select a small stripe size. The default stripe size is 64 KB.
Write Policy This option sets the caching method to write-back or write-through.
In Write-back caching, the controller sends a data transfer completion signal to the host when the controller cache has received all the data in a transaction.
In Write-through caching, the controller sends a data transfer completion signal to the host when the disk subsystem has received all the data in a transaction. This is the default setting in cluster mode.
Write-through caching has a data security advantage over write-back caching, whereas write-back caching has a performance advantage over write-through caching.
Read-ahead This option enables the SCSI read-ahead feature for the logical drive. You can set this parameter to No-Read-Ahead, Read-ahead, or Adaptive.
No-Read-Ahead specifies that the controller does not use read-ahead for the current logical drive.
Read-ahead specifies that the controller uses read-ahead for the current logical drive.
Adaptive specifies that the controller begins using read-ahead if the two most recent disk accesses occurred in sequential sectors. If all read requests are random, the algorithm reverts to No-Read-Ahead, however, all requests are still evaluated for possible sequential operation. This is the default setting.
Cache Policy This parameter applies to reads on a specific logical drive. It does not affect the Read ahead cache.
Cached I/O specifies that all reads are buffered in cache memory.
Direct I/O specifies that reads are not buffered in cache memory. This is the default setting.
Direct I/O does not override the cache policy settings. Data is transferred to cache and the host concurrently. If the same data block is read again, it comes from cache memory.
Press <Esc> to exit the Advanced Menu.
10. After you define the current logical drive, choose Accept and press <Enter>. If space remains in the arrays, the next logical drive to be configured appears. Repeat steps 6 to 9 to configure another logical drive. If the array space has been used, a list of the existing logical drives appears. Press any key to continue and respond to the Save prompt.
11. Initialize the logical drives you have just configured.
View/Add Configuration allows you to associate logical drives with multiple arrays (this is known as spanning of arrays). The existing configuration is left intact, so you can also use View/Add Configuration simply to look at the current configuration.
1. Choose Configure from the PERC 2/DC BIOS Configuration Utility main menu.
2. Choose View/Add Configuration from the Configure menu. An array selection window displays, showing the devices connected to the current controller.
Hot key information appears at the bottom of the screen.
The hot key functions are:
<F2> Display the manufacturer data and PERC 2/DC error count for the selected drive.
<F3> Display the logical drives that have been configured.
<F4> Designate the selected drive as a hot spare.
<F10> Display the logical drive configuration screen.
3. Press the arrow keys to choose specific physical drives. Press the spacebar to associate the selected physical drive with the current array. The indicator for the selected drive changes from READY to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means disk drive 3 in array 2.
Try to use drives of the same capacity in a specific array. If you use drives with different capacities in an array, all the drives in the array is treated as if they have the capacity of the smallest drive in the array.
The number of physical drives in a specific array determines the RAID levels that can be implemented with the array.
RAID 0 requires one or more physical drives per array.
RAID 1 requires two physical drives per array.
RAID 5 requires at least three physical drives per array.
RAID 10 requires at least four physical drives per array.
RAID 50 requires at least six physical drives per array.
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Dell does not recommend using RAID 0 in the cluster environment. RAID 0 is not redundant and provides no data protection. |
4. Press <Enter> when you are finished creating the current array. To continue defining arrays, repeat step 3. To begin logical drive configuration, go to step 5.
5. Press <F10> to configure logical drives. The logical drive configuration screen appears, as shown below:
The logical drive that is currently being configured and any existing logical drives are displayed. The column headings are:
LD - The logical drive number,
RAID - The RAID level,
Size - The logical drive size,
#Stripes - The number of stripes (physical drives) in the associated physical array,
StrpSz - The stripe size, and
Drive-State - The state of the logical drive.
6. Set the RAID level for the logical drive. Highlight RAID and press <Enter>. The available RAID levels for the current logical drive appear. Select a RAID level and press <Enter> to confirm. See Chapter 3 RAID Levels for an explanation of the RAID levels.
7. Set the spanning mode for the current logical drive. Highlight Span and press <Enter>. The choices are:
CanSpan Array spanning is enabled for the current logical drive. The logical drive can occupy space in more than one array.
NoSpan Array spanning is disabled for the current logical drive. The logical drive can occupy space in only one array.
PERC 2/DC supports spanning for RAID 1 and RAID 5 arrays only. You can span two or more contiguous RAID 1 logical drives into a RAID 10 array, or two or more contiguous RAID 5 logical drives into a RAID 50 array.
For two arrays to be spannable, they must have the same stripe width (they must contain the same number of physical drives) and they must be consecutively numbered. For example, assuming Array 2 contains four disk drives, it can be spanned only with Array 1 and/or Array 3, and only if Arrays 1 and 3 also contain four disk drives. If the two criteria for spanning are met, PERC 2/DC automatically activates spanning. If the criteria are not met, the Span setting makes no difference for the current logical drive. Highlight a spanning option and press <Enter>.
8. Set the logical drive size. Move the cursor to Size and press <Enter>. By default, the logical drive size is set to all available space in the array(s) being associated with the current logical drive, accounting for the Span setting.
9. Open the Advanced menu to set the remaining options.
Stripe size This parameter specifies the size of the segment written to each disk in a RAID 1 or 5 logical drive. You can set the stripe size to 2 KB, 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or 128 KB. A larger stripe size produces higher read performance, especially if your computer does mostly sequential reads. However, if your computer does random read requests more often, choose a smaller stripe size. The default is 64 KB.
Write Policy This parameter specifies the cache write policy. You can set the write policy to write-back or write-through.
In Write-back caching, the controller sends a data transfer completion signal to the host when the controller cache has received all the data in a transaction. This setting is not recommended.
In Write-through caching, the controller sends a data transfer completion signal to the host when the disk subsystem has received all the data in a transaction. This is the default setting for cluster mode.
Write-through caching has a data security advantage over write-back caching, whereas write-back caching has a performance advantage over write-through caching.
Read-ahead This parameter enables the SCSI read-ahead feature for the logical drive. You can set this parameter to No-Read-Ahead, Read-ahead, or Adaptive.
No-Read-Ahead specifies that the controller does not use read-ahead for the current logical drive.
Read-ahead specifies that the controller uses read-ahead for the current logical drive.
Adaptive specifies that the controller begins using read-ahead if the two most recent disk accesses occurred in sequential sectors. If all read requests are random, the algorithm reverts to No-Read-Ahead; however, all requests are still evaluated for possible sequential operation. This is the default setting.
Cache Policy This parameter applies to reads on a specific logical drive. It does not affect the Read ahead cache.
Cached I/O specifies that all reads are buffered in cache memory.
Direct I/O specifies that reads are not buffered in cache memory. This is the default setting.
Direct I/O does not override the cache policy settings. Data is transferred to cache and the host concurrently. If the same data block is read again, it comes from cache memory.
Press <Esc> to exit the Advanced Menu.
10. After you define the current logical drive, choose Accept and press <Enter>. If space remains in the arrays, the next logical drive to be configured appears. Repeat steps 6 to 9 to configure another logical drive. If all array space is used, a list of the existing logical drives appears. Press any key to continue. Respond to the Save prompt.
11. Initialize the logical drives you have just configured.
Initialize each new logical drive you configure. You can initialize the logical drives using:
- Batch Initialization. The Initialize option in the main menu lets you initialize up to eight logical drives simultaneously.
- Individual Initialization. The Objects/Logical Drive action menu for an individual logical drive has an Initialize option.
Batch Initialization
To initialize logical drives using the batch initialization procedure:
1. Choose Initialize from the BIOS Configuration Utility main menu. A list of the current logical drives appears, as shown below:
2. Press the arrow keys to select all drives. Press the spacebar to select the selected logical drive for initialization. Press <F2> to select/deselect all logical drives.
3. When you have finished selecting logical drives, press <F10> and choose Yes from the confirmation prompt. The progress of the initialization for each drive is shown in bar graph format.
4. When initialization is complete, press any key to continue.
Press <Esc> to display the main menu.
Individual Initialization
2. Select the logical drive to be initialized. The following appears:
3. Choose the Initialize option from the action menu. Initialization progress appears as a bar graph on the screen.
4. When initialization completes, press any key to display the previous menu.
You can do low-level formatting of SCSI drives using the BIOS Configuration Utility.
Since most SCSI disk drives are low-level formatted at the factory, this step is usually not necessary. Usually, you must format a disk if:
- the disk drive was not low-level formatted at the factory, or
- an excessive number of media errors have been detected on the disk drive.
Media Errors
Check the View Drive Information screen for the drive to be formatted. You can view this screen by choosing Objects from the Management menu. Select the Physical Drives option, and choose a device. Press <F2>.
The error count displays at the bottom of the properties screen. If you feel that the number of errors is excessive, you should probably format the disk drive. If more than 32 media errors were detected, PERC 2/DC automatically puts the drive in FAIL state. This occurs even in a degraded RAID set. The errors are displayed as they occur. In cases such as this, formatting the drive can clear up the problem.
You do not have to choose Format to erase existing information on your SCSI disks, such as a DOS partition. That information is erased when you initialize logical drives.
Formatting Drives
You can format the physical drives using:
- Batch Formatting. The Format option in the PERC 2/DC BIOS Configuration Utility main menu lets you format up to eight disk drives simultaneously.
- Individual Formatting. Choose the Format option from Objects on the Physical Drive action menu for a physical disk drive
Batch Formatting
1. Choose Format from the BIOS Configuration Utility management menu. A device selection window is displayed showing the devices connected to the current controller, as shown below:
2. Press the arrow keys to select all drives. Press the spacebar to select the selected physical drive for formatting. The indicators for selected drives flashes.
3. When you are done selecting physical drives, press <F10> and choose Yes from the confirmation prompt. The indicators for the selected drives changes to FRMT[number], where number reflects the order of drive selection. Formatting may take some time, depending on the number of drives you have selected and the drive capacities.
4. When formatting is complete, press any key to continue.
Press <Esc> to display the main menu
Individual Formatting
1. Choose the Objects option from the PERC 2/DC BIOS Configuration Utility main menu. Choose the Physical Drive option from the Objects menu. A device selection window displays, showing the devices connected to the current controller, as shown below:
2. Press the arrow keys to select the physical drive to be formatted and press <Enter>. The following action menu appears:
3. Choose the Format option from the action menu and respond to the confirmation prompt. Formatting can take some time, depending on the drive capacity.
4. When formatting completes, press any key to display the previous menu.
Rebuilding Failed Disk Drives
If a disk drive fails in an array that is configured as a RAID 1 or 5 logical drive, you can recover the lost data by rebuilding the drive.
Rebuild Types
The rebuild types are:
Table 8. Rebuild Types for Failed Disk Drives
|
Type |
Description |
|
Automatic Rebuild |
If you have configured hot spares, PERC 2/DC automatically tries to use them to rebuild failed disks. Display the Objects/Physical Drive screen while a rebuild is in progress. The drive indicator for the hot spare disk drive has changed to REBLD A[array number]-[drive number], indicating the disk drive being replaced by the hot spare. |
|
Manual Rebuild |
Manual rebuild is necessary if no hot spares with enough capacity to rebuild the failed drives are available. Select the PERC 2/DC BIOS Configuration Utility main menu Rebuild option or the Rebuild option on the Objects/Physical Drive menu. |
Manual Rebuild � Rebuilding an Individual Drive
2. Press the arrow keys to select the physical drive to rebuild. Press <Enter>.
- Choose the Rebuild option from the action menu and respond to the confirmation prompt. Rebuilding can take some time, depending on the drive capacity.
4. When rebuild completes, press any key to display the previous menu.
Manual Rebuild � Batch Mode
- Choose Rebuild from the PERC 2/DC BIOS Configuration Utility main menu. A device selection window displays, showing the devices connected to the current controller. The failed drives have FAIL indicators.
2. Press the arrow keys to select any failed drives to be rebuilt. Press the spacebar to select the selected physical drive for rebuild.
3. After selecting the physical drives, press <F10> and select Yes at the prompt. The indicators for the selected drives change to REBLD. Rebuilding can take some time, depending on the number of drives selected and the drive capacities.
4. When rebuild is complete, press any key to continue. Press <Esc> to display the main menu.
|
To use a pre-loaded system drive in the manner described here, you must make it the first logical drive defined (for example: LD1) on the controller it is connected to. This will make the drive ID 0 LUN 0. If the drive is not a boot device, the logical drive number is not critical. |
You may have a SCSI disk drive that is already loaded with software. The drive may be a boot disk containing an operating system. If so, add the PERC device driver to this system drive before you switch to the PERC 2/DC and attempt to boot from it. You can use the PERC 2/DC controller as a SCSI adapter for such a drive by performing the following steps:
1. Connect the SCSI drive to the channel on the PERC 2/DC controller, with proper termination and TID settings.
2. Boot the computer and start the PERC 2/DC BIOS Configuration Utility by pressing <Ctrl> <M>.
3. Choose Easy Configuration from the Configure menu.
4. Press the cursor keys to select the pre-loaded drive.
5. Press the spacebar. The pre-loaded drive should now become an array element.
6. Press <Enter>. You have now declared the pre-loaded drive as a one-disk array. Display the logical drive configuration screen.
7. Set the read policy and cache option on the Advanced menu.
8. Exit the Advanced menu. Highlight Acceptand press <Enter>. Do not initialize.
9. Press <Esc> and choose Yes at the Save prompt.
10. Exit the PERC 2/DC BIOS Configuration Utility and reboot.
11. Set the host system to boot from SCSI, if such a setting is available.
Press <Esc> when the PERC 2/DC BIOS Configuration Utility management menu is displayed to exit PERC 2/DC BIOS Configuration Utility. Choose Yes at the prompt. You must then reboot the computer. The PERC 2/DC BIOS message appears again. Press <Esc> when the BIOS Configuration Utility prompt appears.
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