Logical Drive
A logical drive is a partition in a physical array of disks that is made up of contiguous data segments on the physical disks. A logical drive can consist of any of the following:
•an entire physical array
•more than one entire physical array
•a part of an array
•parts of more than one array
•a combination of any two of the above conditions
Hot Swap
A hot swap is the manual replacement of a defective physical disk unit while the computer is still running. When a new drive has been installed, you must issue a command to rebuild the drive. MegaRAID can be configured to detect the new disks and to rebuild the contents of the disk drive automatically.
SCSI Drive States
A SCSI disk drive can be in one of these states:
| State | Description |
|
| Online | The drive is functioning normally and is a part of a configured |
|
| (ONLIN) | logical drive. |
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| Ready | The drive is functioning normally but is not part of a configured |
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| (READY) | logical drive and is not designated as a hot spare. |
|
| Hot Spare | The drive is powered up and ready for use as a spare in case an |
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| (HOTSP) | online drive fails. |
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| Fail | A fault has occurred in the drive placing it out of service. |
|
| (FAIL) |
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| Rebuild | The drive is being rebuilt with data from a failed drive. |
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| (REB) |
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Logical Drive States
| State | Description |
|
| Optimal | The drive operating condition is good. All configured drives are |
|
|
| online |
|
| Degraded | The drive operating condition is not optimal. One of the |
|
|
| configured drives has failed or is offline. |
|
| Failed | The drive has failed. |
|
| Offline | The drive is not available to MegaRAID. |
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Chapter 2 Introduction to RAID | 13 |