RAID四种模式

lovemin2016

RAID-5 Parity Rotation
RAID-5 under any operating system can use one of four algorithms for the placement of segments among the disks in the array. -Keep in mind in your troubleshooting that there may be an offset throwing everything off. Find the partition table or OS identifier and us this as your definite sector 0. In a RAID 5 there should be two drives with a partition table. One is the first drive in that array and one is the last drive in the array.
Right Synchronous
Left Synchronous,
Left Asynchronous
Right Asynchronous
Left Asynchronous (Backwards Parity Rotation, Standard)
In this layout, the segments are numbered sequentially, starting with the first non-parity drive in the stripe. The parity drive starts at the last drive, and moves backwards one drive per stripe. While this is the hardware 'standard' RAID-5 layout, it is not the default for Linux or Windows 2000, 2003 Server. This is sometimes called backwards parity or 揝tandard Rotation?R-studio supports this mode.

Left Synchronous
In this layout, the segments are numbered sequentially, starting with the first drive in the stripe after the parity. The segments wrap. The parity drive starts at the left-most drive, and moves right one drive per stripe. This is the default RAID-5 segment layout under Linux.
For large reads, this segment layout is the fastest. This is because each consecutive group of segments that is no larger than the total number of disks in the array, will use all the disks in the array.



Right Asynchronous (Forward Parity Rotation)
In this layout, the segments are numbered sequentially, starting with the first non-parity drive in the stripe. The parity drive starts at the right-most drive, and moves left one drive per stripe.


Right Synchronous
In this layout, the segments are numbered sequentially, starting with the first drive in the stripe after the parity. The segments wrap. The parity drive starts at the right-most drive, and moves left one drive per stripe.