Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 104)

88 Brocade Virtual ADX Server Load Balancing Guide
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Hash-based SLB with server persistence
2
Figure 14 shows the persistent hash table for a virtual server port before the rs3 comes up.
FIGURE 14 Hash table before rs3 comes up
Assume the administrator now binds port HTTP of a new real server rs3 to port HTTP of virtual
server vs1. When real server rs3 comes up, the entire persistent hash table is cleared.
Figure 15 shows the persistent hash table for a virtual server port after the rs3 comes up.
FIGURE 15 Hash table after rs3 comes up
Enabling the reassign-on-change mechanism
To enable the reassign-on-change mechanism, enter commands such as the following.
Virtual ADX(config)#server virtual-name-or-ip vs1
Virtual ADX(config-vs-vs1#port http persist-hash reassign-on-change
When reassign-on-change is enabled (the default), the Brocade Virtual ADX reassigns some of the
existing hash table entries on the introduction of a new server.
virtual server vs1 port http
Hash 0
Hash 1
Hash 2
Hash 3
Hash 255
Hash 6
Hash 5
Hash 4
none
none
rs2
rs2
rs1
rs1
rs2
rs1
..............
Persistent Hash table
virtual server vs1 port http
Hash 0
Hash 1
Hash 2
Hash 3
Hash 255
Hash 6
Hash 5
Hash 4
none
none
..............
Persistent Hash table
none
none
none
none
none
none