When replicating VMs for recovery with SRM you may want to prevent replication of stuff like page and swap. Sometimes it's actually strongly recommended by the replication vendor, sometimes you just don't want to consume the network bandwidth it takes to replicate these non-critical systems.
I do want to be clear, however, that it's not a "best practice" to do this all the time: In fact, you should really consider whether the increase in manual administrative steps makes it worthwhile or whether it will cause further difficulty in the future. There are a lot of steps involved, almost all of it manual, and if you decide later on to change this again the 'undoing' could be very onerous!
Nonetheless sometimes there are good reasons to do so, and it had been documented in the past as part of the admin guide. That information is now instead a knowledge base article – the KB tells you how to configure protected virtual machines to use nonreplicated storage as a redirect for either or both of page files and swapfiles.
Check out the process at the KB page here: http://kb.vmware.com/kb/2009324 but again use caution and only do this if you have a very strong reason to do so!