Global Server Load Balancing
Global Server Load Balancing (GSLB) allows us to load-balance services across different geographical regions. For instance, large organizations such as Facebook, eBay, and Microsoft use this technology to load-balance their web services. This might be for proximity reasons, because a user might be redirected to the closest available resource, or to keep redundant services available in case of datacenter failures.
So the main purposes for GSLB are:
Performance; user proximity to the closest available resource
Disaster recovery, where multiple sites can be grouped as primary and standby
Load balancing resources between different multiple locations
GSLB is based upon the use of DNS. So for instance when a user wants to go to www.citrix.com, that user's DNS client will do a number of queries against the different DNS servers, until it gets a response from an authoritative source for that domain. An example might be where NetScaler, which is the authoritative nameserver...
