Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 109)

Brocade Virtual ADX Server Load Balancing Guide 93
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Hash-based SLB with server persistence
2
In the previous example, assume a client now makes an HTTP request for virtual server vs1.
Assume also the client’s IP address hashes to a value of 2. The Brocade Virtual ADX checks the
hash table entry corresponding to hash value 2 in the above persistent hash table. Because no real
server is associated with the hash entry, the Brocade Virtual ADX selects a new real server, such as
rs2, using the SLB predictor and then assigns the server to the hash table entry. This and
subsequent requests from the client will then be serviced by rs2.
Figure 20 shows the new real
server rs2 to service request to the client.
FIGURE 20 Using rs2 to service requests
Displaying persistent hash table entry and statistics
To display the persistent hash table entry and statistics for a virtual server, use rconsole to get into
the BP and enter the show server persist-hash-buckets command.
Syntax: show server persist-hash-buckets virtual-server-name
If you do not specify a virtual server name, all the persistent hash tables for all virtual server ports
for all virtual servers will be displayed.
Table 10 displays the output field description of show server
persist-hash-buckets command.
TABLE 10 Output field descriptions of show server persist-hash-buckets command
Field Description
Virtual server Name of the virtual server.
Port Virtual server port.
Bucket Hash value for hash table entry.
Server Real server assigned to the hash table entry.
Hit Number of times the client IP has hashed to this entry and been serviced
by the associated real server. It is possible for multiple clients to hash to
the same hash entry (bucket).
virtual server vs1 port http
Hash 0
Hash 1
Hash 2
Hash 255 none
rs2
..............
Persistent Hash table
none
rs2
Virtual ADX#rconsole 1 1
Virtual ADX1/1#show server persist-hash-buckets http-vs
Virtual port Persist Hash Buckets:
Virtual Server Port <80>:
Bucket: Server Hit Bucket: Server Hit
45: http-rs1 1
Virtual Server Port <53>:
Bucket: Server Hit Bucket: Server Hit
45: dns-ns 2