1 Displaying GSLB information
TABLE 13 | GSLB policy information (Continued) | |
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This field... |
| Displays... |
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DNS override |
| Indicates whether DNS override is enabled. DNS override replaces the |
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| addresses in a DNS reply with the “best” address from a list of addresses you |
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| configure. This field can have one of the following values: |
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| • DISABLE: The ServerIron ADX does not replace the addresses in DNS |
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| replies with an address from a list you configure. |
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| • ENABLE: The ServerIron ADX replaces the addresses in DNS replies with |
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| an address from a list you configure. |
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| For more information about DNS override, refer to “Enabling DNS override” on |
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| page 33. |
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Modify DNS response TTL | Indicates whether the GSLB ServerIron ADX modifies the TTL in the DNS records | |
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| in DNS responses before sending the responses to the client’s DNS server. This |
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| field can have one of the following values: |
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| • DISABLE: The ServerIron ADX does not modify the TTLs. |
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| • ENABLE: The ServerIron ADX modifies the TTLs. |
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DNS TTL |
| Indicates the value (number of seconds) to which the GSLB ServerIron ADX |
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| changes the TTL in each DNS record in the DNS responses before sending them |
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| to the client’s DNS server. |
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| NOTE: If the Modify DNS response TTL field contains “DISABLE”, the ServerIron |
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| ADX does not change the TTLs, regardless of the value in this field. |
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DNS check interval | Indicates how frequently the GSLB ServerIron ADX refreshes its zone and host | |
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| information with DNS servers. |
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Remote ServerIron ADX status | Indicates how frequently the remote ServerIron ADXs send status updates to the | |
update period |
| GSLB ServerIron ADX through the GSLB protocol. |
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Session capacity threshold | Specifies how close to its maximum session capacity the site ServerIron ADX | |
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| (remote ServerIron ADX) can be and still be eligible as the best site for the |
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| client. If a site ServerIron ADX exceeds the threshold, the site ServerIron ADX is |
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| ineligible to be the best site. |
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Session capacity tolerance | Specifies the percentage by which the number of available sessions on the site | |
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| ServerIron ADX can differ from the number of available sessions on another site |
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| ServerIron ADX and still be considered an equally good site. Refer to “Site |
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| ServerIron ADX’s available session capacity tolerance” on page 10. |
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Round trip time tolerance | Specifies the percentage by which the RTT for one site can differ from the RTT | |
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| for another site without this metric resulting in selection of one site over the |
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| other. |
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Round trip time explore | Indicates the percentage of client requests from a given network for which the | |
percentage |
| GSLB ServerIron ADX intentionally ignores the RTT metric when evaluating the |
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| IP addresses in the DNS reply. The explore percentage prevents the ServerIron |
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| ADX from continually biasing its site selection based on the first ServerIron ADX |
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| to return RTT information. Refer to “Modifying |
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| page 53. |
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Round trip time cache prefix | Indicates the length (number of significant bits) of entries in the GSLB | |
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| ServerIron ADX’s IP address cache. The prefix determines the extent to which IP |
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| addresses are aggregated into entries in the cache. |
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Round trip time cache interval | Indicates how many seconds the GSLB ServerIron ADX keeps an unrefreshed | |
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| RTT cache entry in its cache before the entry ages out. |
176 | ServerIron ADX Global Server Load Balancing Guide |
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