Requested protection disk space usage

Increasing the requested protection of data also increases the amount of space consumed by the data on the cluster.

The parity overhead for N + M protection depends on the file size and the number of nodes in the cluster. The percentage of parity overhead declines as the cluster gets larger.

The following table describes the estimated percentage of overhead depending on the requested protection and the size of the cluster or node pool. The table does not show recommended protection levels based on cluster size.

Number of nodes
[+1n]
[+2d:1n]
[+2n]
[+3d:1n]
[+3d:1n1d]
[+3n]
[+4d:1n]
[+4d:2n]
[+4n]
3
2 +1 (33%)
4 + 2 (33%)
6 + 3 (33%)
3 + 3 (50%)
8 + 4 (33%)
4
3 +1 (25%)
6 + 2 (25%)
2 + 2 (50%)
9 + 3 (25%)
5 + 3 (38%)
12 + 4 (25%)
4 + 4 (50%)
5
4 +1 (20%)
8 + 2 (20%)
3 + 2 (40%)
12 + 3 (20%)
7 + 3 (30%)
16 + 4 (20%)
6 + 4 (40%)
6
5 +1 (17%)
10 + 2 (17%)
4 + 2 (33%)
15 + 3 (17%)
9 + 3 (25%)
3 + 3 (50%)
16 + 4 (20%)
8 + 4 (33%)
7
6 +1 (14%)
12 + 2 (14%)
5 + 2 (29%)
15 + 3 (17%)
11 + 3 (21%)
4 + 3 (43%)
16 + 4 (20%)
10 + 4 (29%)
8
7 +1 (13%)
14 + 2 (12.5%)
6 + 2 (25%)
15 + 3 (17%)
13 + 3 (19%)
5 + 3 (38%)
16 + 4 (20%)
12 + 4 (25% )
4 + 4 (50%)
9
8 +1 (11%)
16 + 2 (11%)
7 + 2 (22%)
15 + 3 (17%)
15+3 (17%)
6 + 3 (33%)
16 + 4 (20%)
14 + 4 (22%)
5 + 4 (44%)
10
9 +1 (10%)
16 + 2 (11%)
8 + 2 (20%)
15 + 3 (17%)
15+3 (17%)
7 + 3 (30%)
16 + 4 (20%)
16 + 4 (20%)
6 + 4 (40%)
12
11 +1 (8%)
16 + 2 (11%)
10 + 2 (17%)
15 + 3 (17%)
15+3 (17%)
9 + 3 (25%)
16 + 4 (20%)
16 + 4 (20%)
8 + 4 (33%)
14
13 + 1 (7%)
16 + 2 (11%)
12 + 2 (14%)
15 + 3 (17%)
15+3 (17%)
11 + 3 (21%)
16 + 4 (20%)
16 + 4 (20%)
10 + 4 (29%)
16
15 + 1 (6%)
16 + 2 (11%)
14 + 2 (13%)
15 + 3 (17%)
15+3 (17%)
13 + 3 (19%)
16 + 4 (20%)
16 + 4 (20%)
12 + 4 (25%)
18
16 + 1 (6%)
16 + 2 (11%)
16 + 2 (11%)
15 + 3 (17%)
15+3 (17%)
15 + 3 (17%)
16 + 4 (20%)
16 + 4 (20%)
14 + 4 (22%)
20
16 + 1 (6%)
16 + 2 (11%)
16 + 2 (11%)
16 + 3 (16%)
16 + 3 (16%)
16 + 3 (16%)
16 + 4 (20%)
16 + 4 (20% )
16 + 4 (20%)
30
16 + 1 (6%)
16 + 2 (11%)
16 + 2 (11%)
16 + 3 (16%)
16 + 3 (16%)
16 + 3 (16%)
16 + 4 (20%)
16 + 4 (20%)
16 + 4 (20%)

The parity overhead for mirrored data protection is not affected by the number of nodes in the cluster. The following table describes the parity overhead for requested mirrored protection.

2x

3x

4x

5x

6x

7x

8x

50%

67%

75%

80%

83%

86%

88%