Starting the RAID BIOS Configuration UtilityDell™ PowerEdge™ Expandable RAID Controller 4/Di User's Guide
Starting the RAID BIOS Configuration Utility
Designating Drives as Hot Spares
Adding Configuration on Disk Support
Using a Pre-loaded SCSI Drive "As-is"
Exiting the RAID BIOS Configuration Utility
The RAID BIOS Configuration Utility configures disk arrays and logical drives. Because the utility resides in the PERC 4/Di BIOS, its operation is independent of the operating systems on your computer.
Use this utility to perform the following:
When the host computer boots, hold the <Ctrl> key and press the <M> key when a BIOS banner such as the following appears:
HA -0 (Bus X Dev X) Type: PERC 4/Di Standard FW x.xx SDRAM=128MB
Battery Module is Present on Adapter
1 Logical Drive found on the Host Adapter
Adapter BIOS Disabled, No Logical Drives handled by BIOS
0 Logical Drive(s) handled by BIOS
Press <Ctrl><M> or <Ctrl><H> to Enable BIOS
For each adapter in the host system, the firmware version, dynamic random access memory (DRAM) size, and the status of logical drives on that controller display. After you press a key to continue, the Management Menu screen displays.
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NOTE: In the RAID BIOS Configuration Utility, pressing <Ctrl><M> has the same effect as pressing <Enter>. |
Perform the following steps to configure arrays and logical drives:
See "Creating Arrays" for more information.
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, 10, and 50. Each controller supports up to eight hot spares.
The methods for designating physical drives as hot spares are:
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 drive as a hot spare:
The drive displays as HOTSP.
A physical drive selection screen appears.
The selected drive displays as HOTSP.
Create arrays using Easy or New Configuration. See "Using Easy Configuration" and "Using New Configuration" for procedures.
In Easy Configuration, each physical array you create is associated with exactly one logical drive. You can modify the following parameters:
If logical drives have already been configured when you select Easy Configuration, the configuration information is not disturbed. Perform the following steps to create arrays using Easy Configuration.
Hot key information displays at the bottom of the screen.
The selected drive changes from READY to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means hard 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 drives in the array are treated as if they have the capacity of the smallest drive in the array.
The Select Configurable Array(s) window appears. It displays the array and array number, such as A-00.
Span information displays in the array box. You can create multiple arrays, then select them to span them.
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NOTE: You can press <F2> to display the number of drives in the array, their channel and ID, and <F3> to display array information, such as the stripes, slots, and free space. |
The window at the top of the screen shows the logical drive that is currently being configured.
The available RAID levels for the current logical drive display.
Stripe Size specifies the size of the segments written to each disk in a RAID 0, 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 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. 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.
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 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 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.
The array selection screen appears if any unconfigured hard drives remain.
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NOTE: The PERC 4 family supports spanning across RAID 1 and 5 arrays only. |
PERC 4/Di supports up to 40 logical drives per controller.
A list of the currently configured logical drives appears.
After you respond to the Save prompt, the Configure menu appears.
See "Initializing Logical Drives" for more information.
If you select New Configuration, the existing configuration information on the selected controller is destroyed when the new configuration is saved. In New Configuration, you can modify the following logical drive parameters:
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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. |
Hot key information appears at the bottom of the screen.
The selected drive changes from READY to ONLINE A[array number]-[drive number]. For example, ONLINE A2-3 means hard drive 3 in array 2.
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NOTE: 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 Select Configurable Array(s) window appears. It displays the array, and array number, such as A-00.
Span information displays in the array box. You can create multiple arrays, then select them to span them.
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NOTE: You can press <F2> to display the number of drives in the array, their channel and ID, and <F3> to display array information, such as the stripes, slots, and free space. |
The logical drive configuration screen appears. Span=Yes displays on this screen if you select two or more arrays to span.
The window at the top of the screen shows the logical drive that is currently being configured as well as any existing logical drives.
A list of the available RAID levels for the current logical drive appears.
The choices are:
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.
PERC 4/Di 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 spanned, 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, PERC 4/Di automatically allows spanning. If the criteria are not met, the Span setting makes no difference for the current logical drive.
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NOTE: The PERC 4 family 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. |
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NOTE: The full drive size is used when you span logical drives; you cannot specify a smaller 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.
Stripe Size specifies the size of the segments written to each disk in a RAID 0, 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 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. 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.
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 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 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.
If space remains in the arrays, the next logical drive to be configured appears.
If the array space has been used, a list of the existing logical drives appears.
See "Initializing Logical Drives" for more information.
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 enable the Configuration on Disk feature.
Hot key information appears at the bottom of the screen.
The selected drive changes from READY to ONLIN A[array number]-[drive number]. For example, ONLIN A2-3 means hard drive 3 in array 2.
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NOTE: 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 Select Configurable Array(s) window appears. It displays the array, and array number, such as A-00.
Span information, such as Span-1, displays in the array box. You can create multiple arrays, then select them to span them.
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NOTE: You can press <F2> to display the number of drives in the array, their channel and ID, and <F3> to display array information, such as the stripes, slots, and free space. |
The logical drive configuration screen appears. Span=Yes displays on this screen if you select two or more arrays to span.
The available RAID levels for the current logical drive appear.
The choices are:
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.
PERC 4/Di 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 spanned, 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 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, PERC 4/Di automatically activates spanning. If the criteria are not met, the Span setting makes no difference for the current logical drive.
By default, the logical drive size is set to all available space in the array(s) associated with the current logical drive, accounting for the Span setting.
The choices are:
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.
PERC 4/Di 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 spanned, 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 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, PERC 4/Di automatically activates spanning. If the criteria are not met, the Span setting makes no difference for the current logical drive.
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NOTE: The full drive size is used when you span logical drives; you cannot specify a smaller drive size. |
Stripe Size specifies the size of the segment written to each disk in a RAID 0, 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, select a smaller stripe size. The default is 64 KB.
Write Policy 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.
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 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 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.
If space remains in the arrays, the next logical drive to be configured appears.
If all array space is used, a list of the existing logical drives appears.
See "Initializing Logical Drives" for more information.
The RAID controller supports configuration on disk (drive roaming). Configuration on disk saves configuration information both in the PERC 4/Di non-volatile random access memory (NVRAM) and on the hard drives attached to PERC 4/Di. If PERC 4/Di is replaced, the new PERC 4/Di controller can detect the RAID configuration, maintaining the integrity of the data on each drive even if the drives have changed target IDs.
Perform the following steps to add Configuration on Disk support:
Initialize each new logical drive you configure. You can initialize the logical drives individually or in batches (up to 40 simultaneously).
A list of the current logical drives appears.
The progress of the initialization for each drive is shown in bar graph format.
Initialization progress appears as a bar graph on the screen.
This RAID controller supports 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 the whole array.
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.
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NOTICE: The deletion of the logical drive can fail under certain conditions: 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 |
To delete logical drives, perform the following steps:
The logical drives display.
This deletes the logical drive and makes the space it occupied available for you to make another logical drive.
You can do low-level formatting of SCSI drives using the RAID BIOS Configuration Utility. Because most SCSI hard drives are low-level formatted at the factory, this step is usually not necessary. You must format a disk only if:
To format a drive, perform the following steps:
A device selection window displays the devices connected to the current controller.
Formatting can take some time, depending on the drive capacity.
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CAUTION: Do not terminate the format process, as it makes the drive unusable. The drive would have to be formatted again. |
If a hard drive fails in an array that is configured as a RAID 1, 5, 10, or 50 logical drive, you can recover the lost data by rebuilding the drive.
Table 4-1 describes automatic and manual rebuilds.
Table 4-1. Rebuild Types
A device selection window displays the devices connected to the current controller.
Rebuilding can take some time, depending on the drive capacity.
A device selection window displays the devices connected to the current controller. The failed drives display as FAIL.
The selected drives change to REBLD. Rebuilding can take some time, depending on the number of drives selected and the drive capacities.
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NOTE: 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. |
If you have a SCSI hard drive that is already loaded with software and the drive is a boot disk containing an operating system, add the PERC device driver to this system drive before you switch to the PERC 4/Di and attempt to boot from it. Perform the following steps:
The pre-loaded drive should now become an array element.
You have now declared the pre-loaded drive as a one-disk array.
Do not initialize.
Online volume extension allows the controller to determine the drive capacity. You can use the drive space of a hard drive that was just added to an existing drive array, without rebooting the operating system.
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NOTE: The ability to use this feature for an existing logical drive depends on the firmware version. Older firmware versions may not allow you to enable this feature once you have saved the configuration. |
Perform the following steps to enable online volume extension:
Set this option to Enabled before you add 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.
Select 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.
Perform the following steps to run Check Consistency:
A progress graph for each selected logical drive displays.
(To check an individual drive, select Objects—> Logical Drives on the Management Menu, the desired logical drive(s), then Check Consistency on the action menu.)
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