Using swapcache to speed up external disk writes?

[PeerCorps Trust Fund]

Dear All!

I have set up a gigabit LAN and have been testing the use of a laptop as a file server/NAS over NFS. The server in question has a 2 terabyte external hard disk attached via USB 2.0. The laptop itself has a 120 gigabyte SSD  installed as its main drive. My question is whether there might be a way to use Dragonfly's swapcache on the SSD in order to get the maximum speed out of the network to transfer files to the laptop's SSD while it writes to the external drive simultaneously in the background? Is there a way to for example increase the size of the swapcache to say 50 gigabytes and route the writes to it (and possibly other disks mounted elsewhere)?

I've tested writes directly over the LAN to the SSD and it tops out at around 120 megabytes per second...which is phenomenal. However when writing to the disk I get speeds of around 18-22 megabytes per second. Not horrible, but quite a substantial difference.

Any tips would be extremely appreciated.

M