You say the current total size of blocks is 2GB; you mean that's the size of the entire blockchain? And that's doubled since July 22? And everybody running a full node has a complete copy of that?
It makes me wonder if this sort of growth is sustainable.
Yes the size of the blockchain is around 2 gb now, it is sustainable because the trusted full nodes are run by witnesses which need to keep their hardware up to the requirements.
Easily, http://pricewatch.com lists a 6 Tb drive for $170.
I could put a NAS with 18 TB together for about $1000, with RAID 0
@biophil 2GB isn't bad at all that's still small enough to fit on a cheap flash drive. Some block chains are 20 times that size and run just fine like Ethereum. Storage is super cheap.
Not to mention there's a big difference between storing the whole block chain for archival purposes, and actually needing to backtrack through it regularly. The former is easily done on a mechanical drive because read/write speeds and seek times aren't really an issue. If the latter was the case it would pretty much require a RAID of SSD's to mitigate the speed issue of random seeks and the reading/writing of non sequential sectors on a drive.