Using DNS Server
--> Before any separate physical load balancing device available, companies used DNS server to provide load balancing capabilities.
--> We need to configure multiple A records for particular application with different IP Addresses.
--> Whenever user want to access that application or website that request will goes to DNS Server then the DNS Server gives the IP Address randomly to the users in round robin fashion.
--> The problem with this approach is, DNS does not have capability to know whether the listed server is working or not.
--> If Server is not working and user is tried to access the website then there are chances DNS server may assign the IP Address of the server which is not working.
--> One more problem with this approach is we cannot assign so many servers in DNS server because of limits in DNS responses.
Reference : F5 Website
--> Before any separate physical load balancing device available, companies used DNS server to provide load balancing capabilities.
--> We need to configure multiple A records for particular application with different IP Addresses.
--> Whenever user want to access that application or website that request will goes to DNS Server then the DNS Server gives the IP Address randomly to the users in round robin fashion.
--> The problem with this approach is, DNS does not have capability to know whether the listed server is working or not.
--> If Server is not working and user is tried to access the website then there are chances DNS server may assign the IP Address of the server which is not working.
--> One more problem with this approach is we cannot assign so many servers in DNS server because of limits in DNS responses.
Using Cluster or Software Load Balancing
--> By using Software Load Balancing we can combine two or more physical server into virtual cluster group.
--> When the user want to access the service, they are connected to cluster IP address instead of physical IP Address.
--> Any Physical Server in the cluster can respond to connection request and session starts.
--> The issue with software load balancing is scalability.
--> Each and Every server need to be in touch with other servers to find who should handle the next connection request.
Reference : F5 Website
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