[PLUG] Movie fan needs storage space

[John Jason Jordan]

My current setup:
	Toshiba 5TB USB 3.0 external drive, surely past its warranty
	Synology Dual Bay NAS with one 8TB WD recent purchase, 5 yr
	warranty

The Toshiba is backed up to the Synology nightly with rsync, using
--delete option to make the Synology a mirror of the Toshiba. 

The problem:
The Toshiba currently has about 4TB on it. There is enough available
space that the need for more room is not critical, but the Toshiba is
displaying issues that make me question its continued reliability.
Starting about a month ago I noticed delays when working with files
with Thunar (Xubuntu 14.04). I go to rename a file, the dialog box pops
up, but it is blank for 10-15 seconds before the text appears. I go to
move a file by dragging and dropping and I get a spinning hourglass for
10-15 seconds before the transfer starts. Ditto for all other file
management operations, although if I (e.g.) drag and drop a file, and
after the action completes I immediately drag and drop another file,
the second file goes without the delay. It is possible that these
issues are due to other problems, but the Toshiba is end of life
anyway. And since the Toshiba is a USB drive I am unable to access the
Smart Data on it, if it even has Smart Data, so I'm flying blind here.
I'd rather just replace it and then, if the file management delays
continue, I will deal with them then. 

So what should I do? There are 8TB external USB 3.0 drives out there,
and that was my first thought. But there are a bewildering number of
them out there and trying to figure out warranties is challenging. For
example, there is a WD Mybook that Amazon says has a three year
warranty, but the same drive at other stores says it has a two year
warranty. And there is a Mybook Pro that costs three times as much but
has only a two year warranty. Some of the advertising data has to be
wrong, but figuring out what is wrong and what is right is a confusing
task. And then each drive has competitors, but trying to assess which
drive is best is another task. (I'm mostly only interested in
warranties - I don't need speed or other whiz-bang features.)

Another idea is to forget about external USB drives and just use
another drive in the Synology, or get a second Synology, considering
that I might some day need more than 8TB of space. The problem with
this is that I might have issues with speed. All my equipment and
wiring is GB rated, but I've never used the network to reach primary
storage. Plus, the network is somewhat less reliable than a direct USB
3.0 connection - the cat can easily turn off a switch or knock the
router off the cabinet it rests on, not to mention my inadequate
knowledge of networking. 

I wrote this long query looking for suggestions. Any ideas are welcome!