Technical data

136 Brocade ServerIron ADX Advanced Server Load Balancing Guide
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Interoperability issues with cache servers
2
NetCache C720 cache server
This model of cache server sends HTTP error code 500 in response to an HTTP keep-alive health
check sent by the ServerIron ADX. By default, the ServerIron ADX does not consider this to be a
valid health check response. To work around this issue, configure status code 500 to be a valid
response to the health check. To do so, enter the port http status_code 500 500 command at the
configuration level for the cache server.
CSW with NetCache cache servers
When the ServerIron ADX redirects a TCP SYN to a cache server, the ServerIron ADX uses the
ServerIron ADX port's MAC address as the source MAC address and the cache server's MAC
address as the destination MAC address. The source and destination IP addresses are not
changed. The source IP address is the client's and the destination IP address is the website the
client is requesting.
When the ServerIron ADX receives the SYN-ACK from the cache server, the ServerIron ADX expects
the destination MAC address in the cache server's reply to belong to the destination IP address (the
requested Web site). The ServerIron ADX does not expect the destination MAC address to be the
ServerIron ADX port's MAC address.
If you are using a NetCache cache server, you must enable the server to respond appropriately to
the ServerIron ADX. To do so, access the following URL on the Netcache server:
• http:// cache_IP_address:3132/cache_config/ui_toggle_basic
On this page, disable IP Fast Output. When this feature is disabled, the cache server performs a
route lookup and sends the packet to the correct destination address.
Handling of dynamic cache bypass function
NOTE
The handling of dynamic cache bypass function by some vendors can utilize the source MAC address
tracking feature. This function is now supported in the ServerIron ADX release 12.4.00c. Refer to the
section '“Source MAC address tracking for TCS” on page 58 for further details.
Support for Partner-Ports in Symmetric Active-Active HA TCS
Starting with release 12.400c, the ServerIron ADX supports partner-ports in symmetric
active-active HA TCS setup. The peer ServerIron ADX will not perform TCS again on traffic arriving
on a partner-port, it will simply switch the traffic at Layer 2 to the destined cache server.
Typically, interfaces that receive data traffic from the peer ServerIron ADX in an symmetric
active-active HA TCS setup are configured as partner-ports. The partner-ports must be configured
in the same VLAN as the cache servers. Use the server partner-ports command to define
partner-ports on a ServerIron ADX.
ServerIronADX(config)#server partner-ports ethernet 1/1
Syntax: [no] server partner-ports ethernet portnum