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CERC BIOS Configuration Utility

Dell™ CERC ATA100/4-Channel RAID Controller Configuration Software Guide

  Starting the BIOS Configuration Utility

  Configuring Arrays and Logical Drives

  Configuration On Disk

  Initializing Logical Drives

  Rebuilding Failed Hard Drives

  Deleting Logical Drives

  Checking Data Consistency

  Exiting the CERC BIOS Configuration Utility


You can use the BIOS Configuration Utility to configure arrays and logical drives. Because the utility resides in the RAID controller BIOS, its operation is independent of the operating systems on your system.

The BIOS Configuration Utility is a character-based utility than you can run by pressing <Ctrl><M> when the system boots. Use the BIOS Configuration Utility to perform the following:

Starting the BIOS Configuration Utility

When the host system boots, hold the <Ctrl> key and press the <M> key when the following appears:

Host Adapter-1 Firmware Version x.xx DRAM Size 16 MB

0 Logical Drives found on the Host Adapter

0 Logical Drives handled by BIOS

Press <Ctrl><M> to run CERC BIOS Configuration Utility

For each RAID card in the host system, the firmware version, DRAM size, and the status of logical drives on that card display. If you do not press <Ctrl><M> within a few seconds of the prompt, the system continues the boot procedure. If you press <Ctrl><M>, the Management Menu screen displays.

Configuring Arrays and Logical Drives

Designating Drives as Hot Spares • Logical Drive Settings • Selecting the Configuration Method • Using View/Add Configuration

Perform the following operations for array and logical drive configuration.

  1. Designate hot spares (optional).

See Designating Drives as Hot Spares for more information.

  1. Select a configuration method and create arrays using the available physical drives.

See Selecting the Configuration Method for more information.

  1. Define logical drive(s) using the space in the arrays.

  2. Save the configuration information.

  3. Initialize the new logical drives.

Designating Drives as Hot Spares

Hot spares are physical drives that are powered up along with the RAID drives and usually stay in a standby state. If a hard 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, 5, and 10.

The methods for designating physical drives as hot spares are:

<F4> Key

When you select any configuration option, a list of all physical devices connected to the current controller appears. Perform the following steps to designate a hard drive as a hot spare:

  1. Press the arrow keys to highlight a hard drive that has a READY indicator.

  2. Press <F4> to designate the drive as a hot spare.

The indicator changes to HOTSP.

Objects Menu

Perform the following steps to designate a hard drive as a hot spare using the Objects Menu:

  1. Select Objects—> Physical Drive.

A physical drive selection screen displays.

  1. Select a hard drive and press <Enter> to display the action menu for the drive.

  2. Press the arrow keys to select Make HotSpare and press <Enter>.

The indicator for the selected drive changes to HOTSP.

Logical Drive Settings

Table 1-1 displays the logical drive parameters and default settings. The write policy, read policy, and cache policy can be changed after configuration is complete.

Table 1-1 Logical Drive Parameters and Default Settings 

Parameter

Setting

Stripe Size

64 KB

Write Policy

Write-through

Read Policy

Adaptive

Cache Policy

Direct I/O

Spanning

Enabled

Table 1-2 contains descriptions of the logical drive parameters.

Table 1-2 Logical Drive Parameters and Descriptions 

Parameter

Description

Stripe Size

Stripe Size specifies the size of the segments written to each drive in a RAID 1, 5, or 10 logical drive. You can set the stripe size to 2 KB, 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or 128 KB. The default stripe size is 64 MB.

A larger stripe size provides better 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.

Write Policy

Write Policy specifies the cache write policy. You can set the write policy to Write-back or Write-through. The default is 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. If WriteBack is enabled and the system is quickly turned off and on, the RAID controller may hang when flushing cache memory. Controllers that contain a battery backup will default to WriteBack caching.

In Write-through caching, the controller sends a data transfer completion signal to the host when the drive subsystem has received all the data in a transaction. This is the default.

Write-through caching has a data security advantage over write-back caching, while write-back caching has a performance advantage over write-through caching. You should not use write-back for any logical drive that is to be used as a Novell NetWare volume.

Read Policy

Read Policy enables the IDE read-ahead feature for the logical drive. You can set this parameter to Read-ahead, No Read-ahead or Adaptive. The default is Adaptive.

Read-ahead specifies that the controller uses read-ahead for the current logical drive.

No Read-ahead specifies that the controller does not use read-ahead for the current logical drive.

Adaptive specifies that the controller begins using read-ahead if the two most recent drive 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 sequential operation.

Cache Policy

Cache Policy applies to reads on a specific logical drive. It does not affect the Read-ahead cache. The default is Direct I/O.

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.

Span

Yes: Array spanning is enabled for the current logical drive. The logical drive can occupy space in more than one array.

No: Array spanning is disabled for the current logical drive. The logical drive can occupy space in only one 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 hard drives, it can be spanned only with array 1 and/or array 3, and only if arrays 1 and 3 also contain four hard drives. If the two criteria for spanning are met, the RAID controller automatically allows spanning. If the criteria are not met, the Span setting makes no difference for the current logical drive.

Selecting the Configuration Method

Using Easy Configuration

In Easy Configuration, each physical array you create is associated with one logical drive, and you can modify the following parameters:

If logical drives have already been configured when you select Easy Configuration, the configuration information is not disturbed.

  1. Select Configure from the BIOS Configuration Utility Management Menu.

  2. Select Easy Configuration from the Configure menu.

The array selection menu appears. Hot key information displays at the bottom of the screen. The hot key functions are:

<F2> Display manufacturer data and error count for selected drive.

<F3> Display logical drives that have been configured.

<F4> Designate selected drive as a hot spare.

  1. Press the arrow keys to highlight specific physical drives.

  2. 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 array 2 with hard drive 3.

  1. 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 determines the RAID levels that can be implemented with the array.

  1. Press <Enter> after you finish creating the current array.

The logical drive configuration screen appears. The top of the screen displays 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 in the associated physical array

StrpSz - The stripe size

DriveState - The state of the logical drive

  1. Press the space bar to select configurable arrays

  2. Highlight RAID and press <Enter> to set the RAID level for the logical drive.

The available RAID levels for the current logical drive display.

  1. Select a RAID level and press <Enter> to confirm.

  2. Set the Stripe Size on the Advanced Menu.

  3. Set the Write Policy on the Advanced Menu.

  4. Set the Read Policy on the Advanced Menu.

  5. Set the Cache Policy on the Advanced Menu.

  6. Press <Esc> to exit the Advanced Menu.

  7. When you have defined the current logical drive, select Accept and press <Enter>.

The array selection screen appears if any unconfigured hard drives remain.

  1. Repeat step 3 through step 15 to configure another array and logical drive.

The RAID controller supports up to 40 logical drives per controller.

  1. When finished configuring logical drives, press <Esc> to exit Easy Configuration.

A list of the currently configured logical drives appears, along with a save prompt.

  1. Respond to the Save prompt.

The Configure menu appears.

  1. Initialize the logical drives you have just configured.

See Initializing Logical Drives for more information.

Using New Configuration

In New Configuration, you can select the following parameters for the arrays:

If you select New Configuration, the existing configuration information on the selected controller is destroyed when the new configuration is saved.

NOTICE: Selecting New Configuration erases the existing configuration information on the selected controller. To use the spanning feature and keep the existing configuration, use View/Add Configuration.
  1. Select Configure—> New Configuration from the CERC Configuration Utility Management Menu.

An array selection window displays 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 CERC 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.

  1. Press the arrow keys to highlight specific physical drives.

  2. 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 array 2 with hard drive 3.

  1. 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 are 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.

  1. Press <Enter> after you finish creating the current array.

  2. Repeat step 3 through step 5 to continue defining arrays or go to step 7 to begin logical drive configuration.

  3. Press the space bar to select configurable arrays.

  4. Press <F10> to configure logical drives.

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 in the associated physical array

StrpSz The stripe size

Drive-State The state of the logical drive

  1. Highlight RAID and press <Enter> to select the RAID level for the logical drive.

A list of the available RAID levels for the current logical drive appears. Select a RAID level and press <Enter> to confirm. See the CERC User's Guide for your board for an explanation of the RAID levels.

  1. Highlight Span and press <Enter> to set the spanning mode for the current logical drive.

  2. Highlight a spanning option and press <Enter>.

  3. Move the cursor to Size and press <Enter> to display the logical drive size.

You cannot set the size when using spanning. 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 and for partially used array space. For example, if the previous logical drive used only a part of the space in an array, the current logical drive size is set to the remaining space by default.

  1. Open the Advanced Menu

  2. Set the Stripe Size on the Advanced Menu.

  3. Set the Write Policy on the Advanced Menu.

  4. Set the Read Policy on the Advanced Menu.

  5. Set the Cache Policy on the Advanced Menu.

  6. Press <Esc> to exit the Advanced Menu.

  7. After you define the current logical drive, select Accept and press <Enter>.

If space remains in the arrays, the next logical drive to be configured appears.

  1. Repeat step 7 through step 19 to configure another logical drive.

If the array space has been used, a list of the existing logical drives appears.

  1. Press any key to continue and respond to the Save prompt.

  2. Initialize the logical drives you have just configured.

See Initializing Logical Drives for more information.

Using View/Add Configuration

View/Add Configuration allows you to control the same logical drive parameters as New Configuration without disturbing the existing configuration information. In addition, you can select to enable the configuration on disk feature.

  1. Select Configure View/Add Configuration from the Configure menu.

An array selection window displays 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 CERC 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.

  1. Press the arrow keys to highlight specific physical drives.

  2. 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 array 2 with hard drive 3.

  1. 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 are 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.

  1. Press <Enter> when you have finished creating the current array.

  2. Repeat step 3 through step 5 to continue defining arrays, or go to step 7 to begin logical drive configuration.

  3. Press the space bar to select configurable arrays

  4. Press <F10> to configure logical drives.

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 in the associated physical array

StrpSz The stripe size

Drive-State The state of the logical drive

  1. Highlight RAID and press <Enter> to set the RAID level for the logical drive.

A list of the available RAID levels for the current logical drive appears.

  1. Select a RAID level and press <Enter> to confirm.

  2. Highlight Span and press <Enter> to set the spanning mode for the current logical drive.

  3. Highlight a spanning option and press <Enter>.

  4. Configure RAID 10 by spanning two contiguous RAID 1 logical drives.

The RAID 1 logical drives must have the same stripe size.

  1. Move the cursor to Size and press <Enter> to set the logical drive size.

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 and for partially used array space. For example, if the previous logical drive used only a part of the space in an array, the current logical drive size is set to the remaining space by default.

  1. Open the Advanced Menu to set the Stripe Size.

  2. Set the Write Policy to open the Advanced Menu.

  3. Set the Read Policy on the Advanced Menu.

  4. Set the Cache Policy on the Advanced Menu.

  5. Press <Esc> to exit the Advanced Menu.

  6. After you define the current logical drive, select Accept and press <Enter>.

If space remains in the arrays, the next logical drive to be configured appears.

  1. Repeat step 7 through step 20 to configure another logical drive.

If the array space has been used, a list of the existing logical drives appears.

  1. Press any key to continue and respond to the Save prompt.

  2. Initialize the logical drives you have just configured.

See Initializing Logical Drives for more information.

Configuration On Disk

NOTE: This option is available only if there is a failed RAID controller or a disconnected cable. It does not display during normal operation.

The RAID card supports configuration on disk (drive roaming), which saves configuration information both in the controller NVRAM and on the hard drives attached to the RAID controller. If the RAID card is replaced, the new RAID card can detect the RAID configuration, maintaining the integrity of the data on each drive even if the drives have changed channel and/or target ID.

NOTE: It is important that the new card have no configuration. Make sure that NVRAM Configuration is cleared by selecting Clear Configuration from the Configure menu before you install IDE cables.

Perform the following steps to add configuration on disk if configuration on disk does not match the configuration in the controller's NVRAM.

  1. Press <Ctrl><M> during system boot to run the BIOS Configuration Utility.

  2. Select Configure.

  3. Select View/Add Configuration.

  4. Select Disk when asked to use Disk or NVRAM and select Save.

  5. Press <Esc> to exit the BIOS Configuration Utility.

  6. Reboot the system.

Initializing Logical Drives

Initialize each new logical drive you configure. You can initialize the logical drives using:

Batch Initialization

  1. Select Initialize from the Configuration Utility Management Menu.

A list of the current logical drives displays.

  1. Press the arrow keys to highlight all drives.

  2. Press the spacebar to select the chosen logical drives for initialization or press <F2> to select/deselect all logical drives.

  3. After you finish selecting logical drives, press <F10>.

  4. Select Yes at the confirmation prompt.

The progress of the initialization for each drive displays in bar graph format.

  1. When initialization is complete, press any key to continue or press <Esc> to display the Management Menu.

Individual Initialization

  1. Select Objects—> Logical Drive from the CERC Configuration Utility Management Menu.

  2. Select the logical drive to be initialized.

The following options appear:

  1. Select Initialize on the action menu.

Initialization progress appears as a bar graph on the screen.

  1. When initialization completes, press any key to display the previous menu.

Rebuilding Failed Hard Drives

If a hard 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

Table 1-3 describes automatic and manual rebuilds.

Table 1-3 Rebuild Types 

Type

Description

Automatic Rebuild

If you have configured hot spares, the RAID card automatically tries to use them to rebuild failed drives. Display the Objects—> Physical Drive screen while a rebuild is in progress. The drive indicator for the hot spare hard drive has changed to REBLD A[array number]-[drive number], indicating the hard 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 Rebuild on the Management Menu or the Rebuild option on the Objects—> Physical Drive menu.


NOTE: To enable an automatic rebuild, you must configure one or more hard drives as hot spares when you configure the array. If a hard drive fails and there is no hot spare with enough capacity to replace the failed drive, you must shut down the system, replace the hard drive, and run the BIOS Configuration Utility, WebBIOS, or Array Manager to perform the rebuild manually. The replacement drive is listed as Failed until the manual rebuild begins.

Manual Rebuild – Rebuilding an Individual Drive

  1. Select Objects—> Physical Drive from the Management Menu.

A device selection window displays the devices connected to the current card.

  1. Press the arrow keys to highlight the physical drive to be rebuilt and press <Enter>.

The physical drive action menu appears.

  1. Select Rebuild from the action menu and respond to the confirmation prompt.

Rebuilding can take some time, depending on the drive capacity.

  1. When the rebuild completes, press any key to display the previous menu.

Manual Rebuild – Batch Mode

  1. Select Rebuild from the Management Menu.

A device selection window displays the devices connected to the current controller. The failed drives have FAIL indicators.

  1. Press the arrow keys to highlight the drives to be rebuilt.

  2. Press the spacebar to select the physical drives for rebuild.

  3. After you select the physical drives, press <F10> and select Yes at the confirmation prompt.

The indicators for the selected drives changes to REBLD. Rebuilding can take some time, depending on the number of drives you have selected and the drive capacities.

  1. When the rebuild is complete, press any key to continue.

  2. Press <Esc> to display the Management Menu.

Deleting Logical Drives

CERC offers the ability to delete any unwanted logical drives and use that space for a new logical drive. You can have an array with multiple logical drives and delete a logical drive without deleting the whole array.

NOTE: For more information about deleting logical drives, refer to the CERC RAID Controller User's Guide.

The main benefit is that you are not restricted to sequential or contiguous logical drives when you create logical drives. You can use non-contiguous segments to create logical drives.

After you delete a logical drive, you can create a new one. You can use the configuration utilities to create the next logical drive from the non-contiguous free space (`holes'), and from the newly created arrays. The configuration utility provides a list of configurable arrays where there is a space to configure.

NOTICE: The deletion of the logical drive can fail under certain conditions. Deletion can fail during a rebuild, initialization or check consistency of a logical drive, if that drive has a higher logical drive number than the drive you want to delete.

Perform the following steps to delete logical drives:

  1. Select Objects—> Logical Drive from the Management Menu.

The logical drives display.

  1. Use the arrow key to highlight the logical drive you want to delete.

  2. Press <Del> to delete the logical drive.

This deletes the logical drive and makes the space it occupied available for you to make another logical drive.

Checking Data Consistency

Select Check Consistency to verify the redundancy data in logical drives that use RAID levels 1 or 5.

When you select Check Consistency, the parameters of the existing logical drives on the current controller and a selection menu listing the logical drives by number appear. If a discrepancy is found, it is 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. Perform the following steps to run the Check Consistency.

  1. Select Check Consistency from the BIOS Configuration Utility Management Menu.

  2. Press the arrow keys to highlight the desired logical drives.

  3. Press the spacebar to select or deselect a drive to check.

  4. Press <F2> to select or deselect all the logical drives.

  5. Press <F10> to begin the consistency check.

A progress indicator for each selected logical drive displays.

  1. When the check consistency is finished, press any key to clear the progress display.

  2. Press <Esc> to display the Management Menu.

Exiting the CERC BIOS Configuration Utility

  1. Press <Esc> when the Management Menu appears.

  2. Select YES at the prompt.

  3. Reboot the system.

The CERC BIOS message appears again.

  1. Press <Esc> when the BIOS Configuration Utility prompt appears.

Please read all restrictions and disclaimers.

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