Its value is the number of 1-K blocks in a swap chunk. When allocating swap areas, the values minswapchunks and maxswapchunks come into play. The value for minswapchunks is used to initially allocate space, but for disk-based systems, it is a nop since swap is always available. Normally, this is set to 1 and serves as a way to verify that the first swap device is functional. The maximum amount of swap space available on a given system is determined by a combination of the swchunk size and maxswapchunks .
Larger values are possible, but be aware of the growth of the swaptab table.
A 4096 maxswapchunks value will allow 4 gigabytes of swap to be specified but will also consume 140 K of kernel memory. The manual states that the upper limit for swap is 2 GB, but the real limit is a function of RAM and kernel size. Remember that it is possible to generate a kernel that is too big to boot into memory. This is practical only on very large RAM systems where virtually all processes will be run in memory and swap space will not be used. In this case, a system with 2 GB of RAM could be run with only a few dozen megs of swap space and the rest of the reservation would take place in pseudo-swap.