This is a bad advice. Calibre (as of version 3) doesn't support this mode of operation. If the network disconnects you will most likely corrupt your library database.
Well, if your HDD shuts down mid write all sorts of shit will go wrong too. Few developers test their apps for this case.
With that line of edge case reasoning you should avoid running the majority of desktop software. :]
I run Calibre with a network share that sits on my home NAS since years w/o issues.
A corrupted database in Calibre is a non issue if all you use it for is to move books between your e-reader devices and the library. You just recreate it.
P.S.: Just for example -- the other day my MacBook's SSD filled up as Adobe InDesign was mid write on a huge document. It crashed and the file was corrupted and not recoverable.
While (mid write) 'not enough space' is not the same as 'network mount went missing' or 'SSD kicked the bucket' it's close enough. And this is commercial software that has been around for 25 years.
This is bad advice. Using Calibre while knowing that certain circumstances surrounding a network disconnect might corrupt your library database is better than rejecting Calibre out of hand since it doesn't support network libraries well.
Best of all would be in Calibre's library handling weren't so finicky, but in the absence of that, I use Calibre with a remote share and I'm just very careful about library backups, how long I leave it running, and am patient with the slowness.
How often does your network disconnect? Sure, it would be great if the backend storage system was better at handling atomic operations, but I don't think this is really a huge problem assuming you're not using a really crappy network.
I run Calibre with the library mounted from a NAS. Works fine for my ~2000 book collection. Not as speedy as local SSD, but it is ok.
Does that work okay with multiple machines connected at the same time? I've been worried about what happens when there's a write conflict to the DB. I'd really like a way to easily share and manage my eBook library from both my laptop and desktop.
If I recall correctly you can have the actual database file on the ssd while the books on the network share that would probably improve the speed a bit.
