Very large swap

[Eduardo Morras]

At 07:08 14/10/2011, Dennis Glatting wrote:

>This is kind of stupid question but at a minimum I thought it would 
>be interesting to know.
>
>What is the limitations in terms of swap devices under RELENG_8 (or 9)?
>
>A single swap dev appears to be limited to 32GB (there are 
>truncation messages on boot). I am looking at a possible need of 
>2-20TB (probably more) with as much main memory that is affordable.

I used 40 GB swap in 8.2. I wanted to test if caching files/data on 
memory swap were faster than an ordinary, always the same, standard 
approach of read/write from/to disk when need. It was faster, not a 
lot faster but mesurable. Of course when app exits files/data is lost.

>I am working with large data sets and there are various ways of 
>solving the problem sets but simply letting the processors swap as 
>they work through a given problem is a possible technique.
>
>Processors, memory, storage, and other hardware are open issues but 
>for the minute I'm doing things on the cheap, which, admittedly, has 
>a certain intellectual amusement factor.
>
>TIA