I know that this thread is old, but I think it would also be useful for any, who got here from Google.
For some reasons the command
mount -a doesn't work for all things that is in fstab. I just changed swap partition, and wanted to see, is the syntax right -- alas the
mount doesn't did a trick. The
swapon does; as I found in it's help message the
enables all swaps from the fstab file.