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Available RAIDS:
RAID 0: it is stripe array and requires [minimum] 2 units. In RAID 0 you can set
the Chunksize 4k - 256k. The destination size of the RAID Array will be
the sum of each drive size in array.
RAID 1: mirror array requires 2 units. Destination size will be equal:
(SINGLE)UNIT_SIZE, where (SINGLE) UNIT_SIZE is the size of the
smallest unit in array.
RAID 5: parity algorithm array (required [minimum] 3 units - with the
same capacity). You can choose from the ListBoxes: (layout)parity-
algorithm [left/right] [symmetric/asymmetric]. DESTINATION SIZE:
(NR_OF_UNITS-1)*(SINGLE)UNIT_SIZE, where (SINGLE) UNIT_SIZE is
the size of the smallest unit in array.
The (layout) parity-algorithm in RAID 5 is described below.
To remove RAID, if previously added to Volume Group please enter Console Tool
and first delete Volume Group of the RAID. Then the Remove button will be
enabled. Otherwise simply press Remove button.
You can add spare units to RAID1 and RAID5 arrays. Please remember
that after creation of a RAID, in Function: 'MD[x] Info' will show the
progress of Synchronization. Till the end of this process all actions done
on this array will be performed very slowly.
RAID 5 (layout) parity-algorithm
It is possible to set one of four algorithms of placement data blocks and parity
blocks in matrix. Our default option is left-symmetric, which is the best for large
reads. Other recommended value is left-asymmetric.
Software RAID 5 is not a good choice for writing a lot of very small files!
Left-Asymmetric Algorithm
Unit
S0
Unit
S1
Unit
S2
Unit
S3
0 1 2
Parity
3 4 Parity 5
6 Parity
7
8
Parity 9 10 11
12 13 14
Parity
Left-Symmetric Algorithm
Unit
S0
Unit
S1
Unit
S2
Unit
S3
0 1 2
Parity
4 5
Parity
3
8 Parity
6 7
Parity
9 10 11
12 13 14
Parity
Right-Asymmetric Algorithm
Unit
S0
Unit
S1
Unit
S2
Unit
S3
Parity 0 1 2
3 Parity 4 5
6 7 Parity 8
9 10 11
Parity
Parity 12 13 14
Right-Symmetric Algorithm
Unit
S0
Unit
S1
Unit
S2
Unit
S3
Parity
0 1 2
5 Parity
3 4
7 8
Parity
6
9 10 11
Parity
Parity
12 13 14
Содержание NAS-XSR ENTERPRISE
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