Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) User Manual
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Brocade Virtual ADX Server Load Balancing Guide
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Overview
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Connection assignments with enhanced weighted predictor for enhanced weighted load-balancing
In enhanced weighted load-balancing, the traffic is distributed in the same proportions as in
weighted load-balancing, but the order of distribution is different. With enhanced weighted
load-balancing, the real server with the greatest weight is allocated a connection first, but then the
next connection is allocated to the real server with the next greatest weight, and then to the server
with the next greatest weight on-down-the-line, until all servers have received their first connection.
The process repeats with each real server getting a connection in sequence until each real server
has connections equal to its assigned weight.
shows the distribution pattern for Enhanced Weighted Load-Balancing in an example
configuration with three real servers, A, B, and C. Real Server A has a weight of 1, Real Server B has
a weight of 2, and Real Server C has a weight of 3. The numbers in bold indicate which server
receives the new connection. When the weighted predictor is configured, connections are assigned
as shown in
Weighted and Enhanced Weighted predictors can be enabled as described in:
Load-Balancing Predictor Method”
TABLE 5
SLB with the enhanced weighted predictor
Real Server A
Real Server B
Real Server C
weight = 1
weight = 2
weight = 3
Connections
Server load
a
a.
For the enhanced weighted predictor, the server load is calculated as connections x [combined weights /
server weight] = server load. Fractional remainders are rounded down. If there is a tie, the server with the highest
weight receives the connection.
Connections
Server load
Connections
Server load
0
0 x 6 / 1 = 0
0
0 x 6 / 2 = 0
0
0 x 6 / 3 = 0
0
0 x 6 / 1 = 0
0
0 x 6 / 2 = 0
1
1 x 6 / 3 = 2
0
0 x 6 / 1 = 0
1
1 x 6 / 2 = 3
1
1 x 6 / 3 = 2
1
1 x 6 / 1 = 6
1
1 x 6 / 2 = 3
1
1 x 6 / 3 = 2
1
1 x 6 / 1 = 6
1
1 x 6 / 2 = 3
2
2 x 6 / 3 = 4
1
1 x 6 / 1 = 6
2
2 x 6 / 2 = 6
2
2 x 6 / 3 = 4
1
1 x 6 / 1 = 6
2
2 x 6 / 2 = 6
3
3 x 6 / 3 = 6
1
1 x 6 / 1 = 6
2
2 x 6 / 2 = 6
4
4 x 6 / 3 = 8
1
1 x 6 / 1 = 6
3
3 x 6 / 2 = 9
4
4 x 6 / 3 = 8
2
2 x 6 / 1 = 12
3
3 x 6 / 2 = 9
4
4 x 6 / 3 = 8
2
2 x 6 / 1 = 12
3
3 x 6 / 2 = 9
5
5 x 6 / 3 = 10
2
2 x 6 / 1 = 12
4
4 x 6 / 2 = 12
5
5 x 6 / 3 = 10
2
2 x 6 / 1 = 12
4
4 x 6 / 2 = 12
6
6 x 6 / 3 = 12
2
2 x 6 / 1 = 12
4
4 x 6 / 2 = 12
7
7 x 6 / 3 = 14
2
2 x 6 / 1 = 12
5
5 x 6 / 2 = 15
7
7 x 6 / 3 = 14