Importance of Swappiness value ?

[sumesh]

Hi Guys

Can any one explain me what will be the best value of swapiness for a vps for best performance.

[Edward]

By definition it is "Swappiness is the kernel parameter that defines how much (and how often) your Linux kernel will copy RAM contents to swap. This parameter's default value is “60” and it can take anything from “0” to “100”. The higher the value of the swappiness parameter, the more aggressively your kernel will swap."

The swappiness parameter determines how often your system swaps data out of memory to the swap space. This is a value between 0 and 100 that represents the percentage of memory usage that will trigger the use of swap.

With values close to zero, the system will not swap data to the drive unless absolutely necessary. Remember, interactions with the swap file are "expensive" in that they are a lot slower than interactions with memory, and this difference in read and write speed can cause a significant reduction in an application's performance. Telling the system not to rely on the swap as much will generally make your system faster.

Values that are closer to 100 will try to put more data into swap in an effort to keep more memory free. Depending on your applications' memory profile, or what you are using your server for, this might be the better choice in some cases.