I have a client with an office in two different countries. Each office has a QNAP TS-219P+ NAS drive which holds the office's network drive shared data, which is shared between 5 PCs in one office and 3 PCs in the other.
Office A's 5 PCs can access NAS A's network drive locally
Office B's 3 PCs can access NAS B's network drive locally
For Office A to access NAS B, or Office B to access NAS A they use FTP or the web interface.
We now want both offices to be able to access the same data. I doubt that's going to be possible with the TS-219P NAS units, and we're happy to junk them and start again, but with what?
Office A has a 16 Mbps download, 1 Mbps upload internet connection
Office B has a 30 Mbps download, 5 Mbps upload connection
There's around 20GB of data on each NAS, all Word/Excel/Powerpoint/PDF documents but of course little changes day to day.
Currently we back up to an external hard drive that is taken offsite, and to an Amazon S3 account.
We'd spend about GBP 2000 (US$3500) without worrying about it, but if there are options more costly that would work better, we'd consider it.