Technical data

60 Brocade ServerIron ADX Advanced Server Load Balancing Guide
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Other transparent cache switching options
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To configure source NAT:
• Enable the source NAT feature. You can enable the feature at the cache group level for all
cache servers or at the cache server level for individual servers.
• Configure a source IP address. A source IP address allows the ServerIron ADX to be a member
of more than one sub-net. If the cache server and ServerIron ADX are in different sub-nets,
configure a source IP address that is in the cache server’s sub-net.
To enable source NAT globally for all cache servers and configure a source IP address, enter
commands such as the following:
ServerIron(config)#server source-ip 10.10.10.5
ServerIron(config)#server cache-group 1
ServerIron(config-tc-1)#source-nat
ServerIron(config-tc-1)#dest-nat
These commands configure a source IP address at the global CONFIG level of the CLI, then change
the CLI to the cache group configuration level and enable source NAT and destination NAT. Source
NAT configures the ServerIron ADX to change the source IP address in a client query from the
client’s IP address to configured source IP address. Destination NAT configures the ServerIron ADX
to change the destination IP address of the client’s request to the IP address of the cache server.
Syntax: [no] source-ip ip-addr network-mask default-gateway
NOTE
The gateway parameter is required. If you do not want to specify a gateway, enter "0.0.0.0".
Syntax: [no] source-nat
To enable source NAT on a specific cache server instead of at the cache group configuration level
for all cache servers, enter commands such as the following:
ServerIron(config)#server cache-name C1
ServerIron(config-rs-C1)#source-nat
ServerIron(config-rs-C1)#dest-nat
The commands in this example enable source NAT and destination NAT on cache server C1 only.
This example assumes that the source IP address also is configured as shown in the previous
example.
NOTE
FTP is not supported when source NAT is configured.
Increasing the TCS hash bucket count
The ServerIron ADX supports 256 hash buckets by default. If you do not assign weights to the
cache servers, the software divides the hash buckets evenly among the cache servers. With the
default hash bucket count of 256, there is a limitation of traffic distribution. In a setup with a large
number of cache servers, if one of the cache servers fails, then their remaining cache servers may
get hit by traffic spikes due to limited load balancing by hash buckets.