Storage, storage. It is just incredibly how fast you can eat it up with all the home videos (particularly with the move to 4K UltraHD and 24-36MP cameras). I've actually just about maxed out our Synology DS1812+ and after some early issues with the Synology Hybird-RAID (I switched to pure RAID 6 and things seem fine now), it looks like I'm pretty close to filling out an entire 8x3TB RAID array. I have a backup drive array that is running 8x4TB in an old Drobo Pro as well as a video editing setup with 4x2TB in an even older Drobo original. But with right now it is not that economic to upgrade the 8x3TB to 4TB, so it might make more sense to just get another array and have two of them as the primary storage systems particular since the expansion chassis are very expensive (The DX513 is $533 for a five bay system).
So what are the choices. Well, we could get the updated version
Synology's DiskStation DS1813+ ($1,000 at Amazon, but a quick search shows the same price at Overstock, NextWarehouse and Egghead via Google Shopping. Overstock has on Bank of America signature, there is a 4 bonus point offer and 10% off if you sign up for mailing list) is the updated version of the already praise-worthy DiskStation DS1812+. The new model is also an eight-bay standalone desktop unit with a whopping storage capacity of up to 32TB.
via Synology DiskStation DS1813+ Review & Rating | PCMag.com.
Another option would be to move up the family to the next larger system given more disks seem to allow more scaling, so there is the DS2413+ at $1700 but it does have 12 bays. And you can go to rack mount with the RS2414+ ($1800) or get redundant power supplies RS2414RP+ ($2400).
If we move to racked system, then Synology has a collection of rack expansion units like the RS1214/RP ($1700 street) which provides 12 bay volume expansion and also redundant power supplies for the RP model. The DX1211 ($1300 at Amazon) is the 12 drive array for the DS2413+.
So the choice are scaling up somewhat with the rack's requiring the biggest premium, but are definitely the easiest to manage and install if you already have a rack.
Existing DS1812+ plus DX-510 expansion units at $530. $110/drive
DS1813+ $1000. $125/drive. DX-510 expansion $530. $110/drive
DS2413+ $1700. $142/drive. Dx1211 $1300. $110/drive
RS2414+ $1900. $158/drive. RS1214 $1700. $141/drive
So the main question is whether or not to jump to an updated NAS (if you are doing that, then the RS2414+ looks like a good option given it is rackmounted or just go with a smaller upgrade to more drives in a DX-510 cabinet). Since the Drobo and DroboPro are eventually going to be obsolete. Both are end of life of already, it does seem like long term I'll need two full NAS systems and Synology seems decently committed to the DS1812+ with regular upgrades (vs Drobo which obsoletes their hardware pretty quickly IMHO). So this might be an opportunity to migrate to the RS2414+ as the main NAS, make the DS1812+ the high availability failover server and then retire then move the DroboPro to the video processing array and put away the Drobo. Just a thought...
And of course there is always the just get a multi bay system that has USB 3.0 and put it on a computer. These are just $100 for a 4bay. The main reason not to is just the convenience of a turnkey system. I actually have this with the Drobo which is attached to a Mac Mini and the net is that it is not so fun to have two things fail.