Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 11)

Brocade Virtual ADX Global Server Load Balancing Guide 1
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Chapter
1
Global Server Load Balancing
Global Server Load Balancing overview
Global Server Load Balancing (GSLB) enables a Brocade Virtual ADX device to add intelligence to
authoritative Domain Name System (DNS) servers by serving as a proxy to these servers and
providing optimal IP addresses to the querying clients.
As a DNS proxy, the GSLB Brocade Virtual ADX evaluates the IP addresses in the DNS replies from
the authoritative DNS server for which the Brocade Virtual ADX is a proxy and places the “best”
host address for the client at the top of the DNS response.
NOTE
The server no-remote-l3-check command disables Layer 3 health checks of IPs learned through
GSLB.
NOTE
To use the max hosts/zone feature on a Brocade Virtual ADX, you need to increase the virtual
servers, real servers and server ports to their system maximum values allowed from your active
license. For more information on the maximum values for system resources, refer to the Brocade
Virtual ADX Software Licensing Guide.
On a Brocade Virtual ADX, do not increase the following resources through the system-max
command when using max zone/host feature, or you will run out of memory.
• ip-static-arp 512
• l3-vlan 32
• mac 16384
• ip-route 8192
• ip-static-route 256
• vlan 64
• session-limit 4096
• virtual-interface 64
GSLB provides the following advantages:
• No connection delay
• Client geographic awareness based on DNS request origination
• Distributed site performance awareness
• Fair site selection
• Statistical site performance measurements that minimize impact of traffic spikes
• Best performing sites get fair proportion of traffic but are not overwhelmed
• Protection against "best" site failure