Dell MD3200, MD3220 owner manual 118, Criteria for Enclosure Loss Protection RAID Level

attempts to choose physical disks that provide enclosure loss protection. If you choose to create a disk group by using the Manual method, you must use the criteria specified in Table 9-2.

Table 9-2. Criteria for Enclosure Loss Protection

RAID Level Criteria for Enclosure Loss Protection

RAID level 5 Ensure that all the physical disks in the disk group are located in or RAID level different expansion enclosures.

6Because a RAID level 5 requires a minimum of 3 physical disks, enclosure loss protection cannot be achieved if your storage array has less than 3 expansion enclosures.

Because a RAID level 6 requires a minimum of 5 physical disks, enclosure loss protections cannot be achieved if your storage array has less than 5 expansion enclosures.

RAID level 1 Ensure that each physical disk in a mirrored pair is located in a different expansion enclosure. This enables you to have more than two physical disks in the disk group within the same expansion enclosure.

For example, if you are creating a six physical disk, disk group (3- mirrored pairs), you can achieve enclosure loss protection with only two expansion enclosures by specifying that the physical disk in each mirrored pair are located in separate expansion enclosures. For example:

•Mirror pair 1—Physical disk in enclosure 1, slot 1 and physical disk in enclosure 2, slot 1.

•Mirror pair 2—Physical disk in enclosure 1, slot 2 and physical disk in enclosure 2, slot 2.

•Mirror pair 3—Physical disk in enclosure 1, slot 3 and physical disk in enclosure 2,slot 3.

Because a RAID level 1 disk group requires a minimum of two physical disks, enclosure loss protections cannot be achieved if your storage array has less than two expansion enclosures.

RAID level 0 Because RAID level 0 does not have consistency, you cannot achieve enclosure loss protection.

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Configuration: Disk Groups and Virtual Disks