I received a request from an application team to increase the amount of swap on a Linux server I was building for them. The reason was that their Oracle client install was failing, complaining about not enough swap space.
As the swap was set to 1/2 RAM, I increased it to 1xRAM + 1GB. Way, way back in the olden days, I used to see recommendations to set swap to 2xRAM, but that was back when RAM was < 1GB.
Later, another member of that application team expressed concern over the increased swap space. He said for their app, they preferred swap size to be only 1/2 RAM or a little more. Otherwise, he worried that there would be issues in the long run.
I had never run across any issues due to having excessive swap configured on a server; neirhter had the co-workers I discussed this with. So of course I went searching for more info, and the consensus seemed to indicate that too much swap would not cause problems, nor increase the likelihood that swapping would occur.
Here are a couple of links to sites that have a good discussion of Linux memory management:
I’d love to hear more about this, though – is it really possible, in some situations, to cause problems by configuring a lot of swap space? What would be the red flags? What would you look for in the output of tools such as vmstat or sar, that would prove that too much swap space had caused a performance problem?