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MaxAttach NAS 6000 Administration Guide
RAID 0 +1 Mirrored Sets of Striped Drives
Description
RAID 0+1 is a dual level array that utilizes multiple RAID 1 mirrored sets into a single
array. Two arrays of striped disks are created. The controller then creates a mirror of the
striped array. This technique is used in the MaxAttach NAS 6000 O/S images on drives
C:\ and D:\. The resultant array is 100% fault tolerant with an two exact images. The
failure of one image usually causes the system to automatically failover to the remaining
image.
Fault Tolerance Cost
The fault cost, like RAID 1 is 50% of total available disk space.
Performance
Each drive in the array is duplicated or mirrored. This eliminates the overhead and delay of
parity. A RAID 0 + 1 array offers high data transfer advantages of striped arrays and
increased data accessibility or reads.
Performance is better than RAID 3, striping with dedicated parity, and RAID 5, striping
with distributed parity.
System performance during a drive rebuild is also better than that of parity based arrays,
since data does not need to be regenerated from parity information, but copied from the
other mirrored drive.
Application Focus
High performance applications where absolute data availability is a must.
Array Size
A minimum of three disks is required to implement RAID 0 + 1, although in practical
terms, most RAID 0 + 1 arrays start at four disks. The maximum number of disks is 16.
Chapter #11 - Appendix - Disk Array RAID Concepts
11/07/01 -- Revision 2.0.03A
Chapter #11 - Appendix - Disk Array RAID Concepts
RAID 0 +1 Mirrored Sets of Striped Drives
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