No idea, I actually came to the comments for the same reason: looking for details about the storage.

In my opinion it's either zfs or netapp. Zfs can replicate datasets via zfs send, netapp has a snapmirror functionality that does basically the same.

Also, iirc, netapp is contributor to freebsd, so it might be zfs anyway underneath.

I wouldn't be surprised. Last time I had the pleasure to create a snapshot for a volume in a netapp it kinda felt like creating a zfs snapshot, in term of speed and ease.

I thought of netapp since they're running fancy 768gb boxes. If they spend money well on their hardware, they probably spend money well on their storage too.

Yeah zfs send (and a bunch of other features/architecture choices) have been one of the biggest reasons I'm interested in the zfs ecosystem and kind of keep a lookout for it/finding ways to work it into infrastructure that I build. I know that Hardware RAID is what the big boys use, but assuming the performance hit is OK, the feature set of ZFS with a properly tuned database installation like a match made in heaven, was hoping to have them comment...

I'd recommend you give a look at TrueNAS/FreeNAS, it's basically an open source NetApp alternative, still based on FreeBSD.

Their enterprise version also has HA and other goodies.