1 Global Server Load Balancing overview
Use the round robin selection metric instead of the least response selection metric when you want to prevent the GSLB ServerIron ADX from favoring new or recently recovered sites over previously configured active sites. The Least Response metric can cause the GSLB ServerIron ADX to select a new site or a previously unavailable site that has come up again instead of previously configured sites for a given VIP. This occurs because the GSLB ServerIron ADX has selected the new site fewer times than previously configured sites for the VIP.
In some cases, the least response selection metric can cause the GSLB ServerIron ADX to send client requests to a new or recovered site faster than the site can handle while it is coming up. To avoid this situation, you can configure the GSLB ServerIron ADX to use the round robin selection metric instead of the least response selection metric as the final tie breaker.
The round robin selection metric is disabled by default.
Check the current and maximum values for GSLB resources using the show gslb resource CLI command.
ServerIronADX# show gslb resources
GSLB resource usage:
sites | Current | Maximum |
0 | 128 | |
SIs | 0 | 200 |
SIs' VIPs | 0 | 2048 |
dns zones | 0 | 1000 |
dns hosts | 0 | 1000 |
0 | 1000 | |
dns IP addrs. | 0 | 2048 |
affinities | 0 | 1024 |
affinity groups | 0 | 128 |
static prefixes | 0 | 250 |
user geo prefixes | 0 | 512 |
prefix cache | 0 | 11786 |
RTT entries | 0 | 10000 |
GSLB host policies | 0 | 100 |
If you are configuring more than 256 zones or configuring more than 600 hosts, perform the following tasks.
1.Change the maximum virtual server system parameter to the maximum value supported in the current release. Use the
For the current maximum virtual server value supported, see the table named "The Number of Supported Real Servers, Virtual Servers and Ports" in the ServerIron ADX Server Load Balancing Guide.
2.Change the maximum real server system parameter to the maximum value supported in the current release. Use the
For the current maximum real server value supported, see the table named "The Number of Supported Real Servers, Virtual Servers and Ports" in the ServerIron ADX Server Load Balancing Guide.
3.Change the maximum server port parameter to the maximum value supported in the current release. Use the
For the current maximum server port value supported, see the table named "The Number of Supported Real Servers, Virtual Servers and Ports" in the ServerIron ADX Server Load Balancing Guide.
4.Check your system parameter values using the show default value CLI command.
12 | ServerIron ADX Global Server Load Balancing Guide |
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