RAID 1 Schemes
You can use RAID 1 several ways, depending on how you divide the drive modules between the RAID controllers, how you choose to mirror the drives, and where you put the module you use as a hot spare. The hot spare is a drive that the RAID controller automatically uses to rebuild data if another drive fails. The hot spare is only available to mirrored pairs on the same controller. If all the drive modules are on one controller, the drives can be mirrored in pairs, and the hot spare will be available to all three pairs.
RAID 1 |
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Appears | Disk 1 | Disk 2 |
as |
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Mirror Mirror Mirror Hot spare | Disk 3 |
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If four modules are on the first controller and three modules are on the second controller, the drives on each controller can be mirrored in pairs, with one module as a hot spare for the pair on the second controller.
| RAID 1 |
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| Appears | Disk 1 | Disk 2 |
| as |
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Mirror Mirror | Mirror Hot spare | Disk 3 |
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Planning RAID Storage for the Xserve RAID System | 71 |