--> Imagine a scenario where a pool member went offline due to some reason and all the connections will be load balanced to different pool members according to load balancing method configured on Virtual Server.
--> After some time, The server guy fixed the issue and the pool member came up online. Now Just think, What will happen once the pool member comes up online.
--> The pool member will be bombarded with multiple connection requests according to the load balancing algorithm configured on the Virtual Server.
--> The above situation may lead to the server(pool member) going down offline again as all the new connections from clients forwarded to the server.
--> For example, if you configure a pool to use the Round Robin load balancing method, the system load balances all new connections to the new pool member because the new pool member has the least amount of connections.
--> In order to prevent the above situation, We are going to use the Slow Ramp Time feature on F5 System.
--> Slow Ramp Time feature is enabled by default which is used to send connection requests slowly to the pool member once it comes online after going down.
--> For example, if the Slow Ramp Time setting is set to 5 seconds when a pool member comes up online and has been available for one second, the system begins load balancing 1/5 of the connections that would have been sent to the new pool member had the Slow Ramp Time setting been disabled.
--> The Slow Ramp Time setting controls the number of connections that are sent to a new pool member by specifying the duration, in seconds, that a pool member is in slow ramp mode.
--> The Slow Ramp Time setting represents an approximate number of seconds that the pool member remains in slow ramp mode.
--> During the slow ramp time, The connections will not be load balanced according to the load balancing algorithm.
--> Once the time expires on the pool member then the connections will be load balanced according to the load balancing algorithm.
--> By default slow ramp time is set to 10 seconds on the pool member.
--> Slow Ramp Time setting to a value of 0 (zero) disables the Slow Ramp Time feature of the pool.
--> It is not recommended to disable slow ramp time on the pool as it has adverse effects.
Reference: F5.com,
Md.Kareemoddin,
CCIE # 54759
Super Duper Explanation
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