Heavy load tests have been done by a number of people especially having two recordings ongoing coupled with a couple of dlna clients active. In this case most of the work is being done by the PVR chipset and not the CPU. See no reason why one or two FTP sessions would give any problems.
BTW, just to comment on this.
I am initiating copies from the NAS so that I can leave them running while the PC is off.
Up until now, I have been using the "copy" function built into the NAS's equivalent of Windows Explorer (Synology's File Station). I select a bunch of maybe 60 files, cut, then paste into the NAS's local folder.
The file transfers are then much like under Windows, and obviously deletes each file that has been successfully transferred. (Very important when the transfers can fail if the box goes into standby.)
Transfer rates hover around 3 MB/s, and I do sometimes get brief drop-outs to recordings if the box is also busy at the same time. Worst is when making two recordings whilst watching a third, as you'd expect.
However, this is not the symptom I was talking about with my comments. If the box is undertaking file copies to the NAS, this will often result in an entry in the media list with the broken icon, and text something like "recording has failed for an unknown reason".
This may be because I'm running a 2TB HD which is very nearly full, but it seems like something makes the recording take too long to startup, and the box gives up. I can understand that - there's limited capacity in the box's hardware.
(I've just upgraded my Android tablet from a 3yo 1x1GHz with 512MB RAM to a modern quad-core 1.6GHz. The old tablet was also running custom f/w, and regularly just hit the limits of what that hardware could achieve - basically due to running out of memory more than CPU resource.)
Looking at the process with FTP, d/l speeds are higher, and get higher again as load on the box decreases - 6+ MB/s when no recordings taking place, and the box is paused replaying a recording (IE also no pause activity on the disk). Browsing the Media file list is much slower with FTP going on, but that's only to be expected.
The "Download Station" on the Synology is able to queue multiple FTP's so they happen sequentially, which is just what I need.
However, it's certainly a lot more work to manually key in 60 separate FTP requests than to just grab 60 files in the filesystem browser and cut/paste them to their destination, especially as I have to construct the file names manually.
I don't know if this is viable as a suggested enhancement to the FoxSat's web UI, but under Browse Media Files, would it be possible to add a "Copy the FTP link for this file into the clipboard" option to the OPT+ menu?
Anyway, the FTP process is all the better for performing so much better, and I'll keep an eye out for whether it avoids any impact to box operations.
cheers, Martin