AMCC 9590SE-4ME manual Valid Migration Paths

Unit Object Commands

Warning: Do not split a RAID 1 unit if you are booted from the drives or if the unit is mounted. Once the unit is split, any pending writes cannot be written to the second drive. In addition, the file system on the drive will not be clean.

type=RaidType specifies the RAID type of the destination unit. Possible unit types include raid0, raid1, raid5, raid10, raid50, or single.

For example, type=raid5 indicates the destination unit is RAID-5. The type=single is a special case of the migrate command. It splits the source unit RAID-1 or TWINSTOR into multiple Single units.

Note: You can only migrate a unit to a RAID level that has the same or more capacity as the existing one. A four-drive RAID 5 unit can migrate to a four-drive RAID 0, but a four-drive RAID 0 unit cannot migrate to a four-drive RAID 5, without adding another drive, due to the need for additional storage capacity for parity bits.

The following table illustrates valid migration paths:

Table 9: Valid Migration Paths

			Destination
Source	R0	R1	R5	R10	Single	Spare
R0	Yes	No	Yes	Yes	No	No
R1	Yes	No	Yes	Yes	Yes	No
R5	Yes	No	Yes	Yes	No	No
R10	Yes	No	Yes	Yesa	No	No
Single	Yes	Yes	Yes	Yes	No	No
Spare	No	No	No	No	No	No

a.When migrating a RAID 10 to a RAID 10, the only change you can make is the stripe size.

disk=p:-p..consists of a list of ports (disks) to be used in addition to the source disks in the construction of the destination unit. One or more ports can be specified. Multiple ports can be specified using a colon (:) or a dash (-) as port index separators. A dash indicates a range and can be mixed with colons. For example disk=0:1:2-5:9:12indicates port 0, 1, 2 through 5 (inclusive), 9 and 12.

www.3ware.com 65