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CERC Manager

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

  Starting CERC Manager

  Using CERC Manager in Linux GUI Mode

  Configuring Arrays and Logical Drives

  Rebuilding Failed Hard Drives

  Deleting Logical Drives

  Checking Data Consistency

  Exiting the CERC Manager


The CERC Manager is a character-based, non-GUI utility that configures and monitors RAID systems. CERC Manager runs under MS-DOS and MS-DOS-compatible operating systems, including:

Starting CERC Manager

To start the Manager, make sure the program file is in your file path. Table 3-1 shows the command to type to start the CERC Manager, depending on the operating system.

Table 3-1 Commands Used to Start CERC Manager

Operating System

Command

DOS

MEGACONF

Novell NetWare

load DELLMGR

Red Hat Linux

DELLMGR

Other

See the software guide for the operating system.

Using CERC Manager in Linux GUI Mode

On a Linux system, for CERC Manager to work correctly in a terminal in GUI Mode, you must:

Perform the procedure below if you use console, gnome terminal, or xterm.

The linux console mode, which you select from the terminal with the File —> Linux Console command, works correctly by default. The text mode console (non-GUI) also works correctly by default.

To prepare the system to use CERC Manager, perform the following steps:

  1. Start the Terminal.

  2. Before you enter dellmgr to start CERC Manager, type the following commands:

TERM=linux

Export TERM

  1. Select Settings—> Keyboard—> Linux Console from the Terminal menu.

NOTE: On a Linux 8.0 system, when you run CERC Manager (v. 5.23) from a Gnome-terminal in XWindows, the <F10> key cannot be used to create a logical drive. Instead, you can use the alternate keys <Shift><0>. (This is not an issue if Xterm is used to call dellmgr). The following is a list of alternate keys you can use in case of problems with keys <F1> through <F6>, and <F10>:

Configuring Arrays and Logical Drives

Designating Drives as Hot Spares • Selecting the Configuration Method • Using Auto Configuration • Using Easy Configuration • Using New Configuration • Using View/Add Configuration • Initializing Logical Drives

Perform the following operations for array and logical drive configuration:

  1. Designate hot spares (optional). See Designating Drives as Hot Spares for more information.

  2. Select a configuration method. See Selecting the Configuration Method for more information.

  3. Create arrays using the available physical drives.

  4. Define logical drives using the arrays.

  5. Save the configuration information.

  6. Initialize the 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, and 5. The RAID controller supports up to two hot spares. Refer to the CERC User's Guide for your board for an explanation of hot spares.

The two methods for designating physical drives as hot spares are:

<F4> Key

When you select any configuration option in the Configure menu, all physical devices connected to the current card appear. Perform the following steps to designate a hard drive as a hot spare:

  1. Select a configuration method on the Configure menu.

The list of hard drives displays.

  1. Press the arrow keys to highlight hard drives that have READY indicators.

  2. Press the spacebar to select the hard drives.

  3. Press <F4> to designate the drives as a hot spares.

The indicator changes to HOTSP.

Objects Menu

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

  1. Select Objects—> Adapter—> Physical Drive.

A physical drive selection screen displays.

  1. Press the spacebar to 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>.

  3. Select YES at the confirmation prompt.

The indicator for the selected drive changes to HOTSP.

Selecting the Configuration Method

Automatic Configuration

In Automatic Configuration, the RAID card examines the physical drives connected to it and automatically configures them into arrays and logical drives.

If logical drives have already been configured when you select Automatic Configuration, the configuration information is not disturbed. See Using Auto Configuration for more information.

Using Auto Configuration

In Auto Configuration, the RAID controller examines the physical drives connected to it and automatically configures them into arrays and logical drives. The RAID card uses the following configuration guidelines in the following sequence:

  1. Gather drives with the same capacity into groups of five, four, or three. These groups become arrays associated with RAID level 5 logical drives.

  2. Gather pairs of drives with the same capacity together. These pairs become arrays associated with RAID 1 logical drives.

  3. Configure any remaining single hard drives as arrays associated with RAID 0 logical drives.

Logical Drive Settings

Table 3-2 displays the logical drive parameters and default settings. The write policy, read policy, and cache policy can be changed after configuration is complete.

Table 3-2 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 3-3 contains descriptions of the logical drive parameters.

Table 3-3 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. Adapters 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.

Performing an Auto Configuration

  1. Designate hot spares (optional, but if chosen, should be done first).

  2. Select Configure from the CERC Manager Main Menu.

  3. Select Automatic Configuration from the Configure menu and respond to the confirmation prompt.

The logical drives that result from Automatic Configuration display on the screen with a save prompt.

  1. Select YES to save the configuration.

  2. If you chose YES at the space prompt, initialize the logical drives.

See Initializing Logical Drives for additional information.

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 CERC Manager Main Menu.

  2. Select Configure—> Easy Configuration.

The array selection menu displays. The 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.

  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 MASTER to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means hard drive 3 in array 2.

  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 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.

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

The logical drive configuration screen appears. 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 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. Open the Advanced Menu.

  3. Set the Stripe Size on the Advanced Menu.

  4. Set the Write Policy on the Advanced Menu.

  5. Set the Read Policy on the Advanced Menu.

  6. Set the Cache Policy on the Advanced Menu.

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

  8. After you finish defining 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 16 to configure another array and logical drive.

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

A list of the currently configured logical drives appears. You are prompted to save the configuration.

  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 modify the following array parameters:

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

  1. Select Configure from the CERC Manager Main Menu.

  2. Select Configure—> New Configuration.

An array selection window displays the devices connected to the current card. Hot key information appears 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.

<F10> Display the logical drive configuration screen.

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

  2. Press the spacebar to select physical drives with the current array.

The indicator for the selected drive changes from MASTER to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means hard drive 3 in array 2.

  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 is treated as though 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.

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

  2. Repeat step 3 through step 6 to continue defining arrays, or go to step 8 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

DriveState - The state of the logical drive

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

The available RAID levels for the current logical drive are listed.

  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 the 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 and use the whole capacity of the hard drives.

  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.

  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 the current logical drive is defined, select Accept and press <Enter>.

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

  1. Repeat step 8 through step 22 to configure another logical drive.

If all 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 parameters as New Configuration without disturbing the existing configuration information.

  1. Select Configure on the CERC Manager Main Menu.

  2. Select Configure—> View/Add Configuration.

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 the physical drives.

  2. Press the spacebar to select physical drives to be associated with the current array.

The indicator for the selected drive changes from MASTER 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> to end the selection process.

  2. Repeat step 3 to continue defining arrays, or go to step 8 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 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 in the associated physical array

StrpSz - The stripe size

DriveState - The state of the logical drive

  1. Highlight RAID 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. Highlight Span and press <Enter> to display the spanning options 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 and use the whole capacity of the hard drives.

  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.

  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 are finished defining 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 8 to step 22 to configure another logical drive.

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

  1. Press any key to continue.

You are prompted to save the configuration.

  1. Respond to the Save prompt.

  2. Initialize the logical drives you have just configured.

See Initializing Logical Drives for more information.

Initializing Logical Drives

You should initialize each new logical drive you configure. You can initialize the logical drives in two ways:

Batch Initialization

Perform the following steps to initialize more than one logical drive at a time:

  1. Select Initialize from the CERC Manager Main Menu.

A list of the current logical drives appears.

  1. Press the arrow keys to highlight all drives to be initialized.

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

  3. When you have selected the logical drives, press <F10> and select YES at the confirmation prompt.

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

  1. When initialization is complete, press any key to continue.

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

Individual Initialization

Perform the following steps to initialize one logical drive at a time:

  1. Select Objects—> Logical Menu from the CERC Manager Main Menu.

  2. Select the logical drive to be initialized.

The logical drive action menu displays.

  1. Select Initialize from the action menu.

The progress of the initialization appears as a 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 configured as a RAID 1 or 5 logical drive, you can recover the lost data by rebuilding the drive. If a rebuilding spare fails, a new rebuild is started using a second spare, if available. The capacity of the second spare must be equal to or greater than that of the failed drive.

Rebuild Types

Table 3-4 describes automatic and manual rebuilds.

Table 3-4 Rebuild Types 

Type

Description

Automatic Rebuild

If you have configured hot spares, the RAID controller 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 CERC Manager Main Menu or Rebuild on the Objects—> Physical Drive menu.

Manual Rebuild – Rebuilding an Individual Drive

  1. Select Objects—> Physical Drive to display the devices connected to the current card.

  2. Press the arrow keys to select the physical drive to be rebuilt and press <Enter>.

The list displays of the actions for the physical drives.

  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 CERC Manager Main 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 chosen physical drives for rebuild.

  3. After selecting the physical drives, press <F10>

  4. At the confirmation prompt, press <Y> to accept.

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

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

  2. Press <Esc> to display the Main 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 <F5> 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 CERC Manager Main 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 consistency check is finished, press any key to clear the progress display.

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

Exiting the CERC Manager

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

  2. Select YES at the prompt.

A message appears if uninitialized logical drives remain in the system.

  1. 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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