Swapping

The machine where a ActiveSpaces® Transactions node runs should always have enough available physical memory so that no swapping occurs on the system. ActiveSpaces® Transactions gains much of its performance by caching as much as possible in memory. If this memory becomes swapped, or simple paged out, the cost to access it increases by many orders of magnitude.

On Linux one can see if swapping has occurred using the following command:

$ /usr/bin/free
             total       used       free     shared    buffers     cached
Mem:       3354568    3102912     251656          0     140068    1343832
-/+ buffers/cache:    1619012    1735556
Swap:      6385796          0    6385796

On Solaris, the following command can be used:

$ /etc/swap -l
swapfile             dev  swaplo blocks   free
/dev/dsk/c1t0d0s1   118,9      16 16780208 16780208