You don’t have to buy a Synology box or have an old PC loaded up with a RAID Array. In the old days a Consumer NAS was a single Hard Drive and funny thing was it cost as much as a Synology.
I have here a PogoPlug Pro and a 2TB Western Digital WD20OURX slapped into a Chassis that use to house a Lorex 16channel DVR.
Surprisingly I didn’t have to Modify the case for everything to fit. I used a 12 Volt 5 Amp Power Brick and a Buck Converter to get a 5 Volt rail for the Hard Drive. The PogoPlug has a built in unused SATA Port. To completely keep the 2TB drive free I used a 8GB USB Thumb Drive to be the Host Partition for the IPKG Optware Package Manager.
For giggles I reused the front USB on the Case. I have it going to a USB2TTL Adapter for emergencies.
In all 90% of this build was Software. Had to setup the Thumb Drive and Hard Drive partitions, install Optware, upgrade Busybox along with Samba, BFTPD and RSYNC. I also ended up installing Lighttpd for future use.
For my use this is just fine and it’s honestly fast for File Transferring over the Network. I was able to get 500GB onto it with in 30 minutes.
The only thing I couldn’t get working was the WiFi Radio. I might try changing it out.