rsync.net is not built on a cloud platform - we own (and have built) all of our own platform. Our storage arrays, as we call them, are 2U “head units” with x16 2.5" drive slots and one or more SAS HBAs.

ZFS makes good use of fast cache storage so, after using up two drive slots for our boot mirror (which is always a mix of two totally different SSDs) we have room for up to 14 more SSDs for read (L2ARC) and write (SLOG) cache. ZFS is also RAM hungry so we choose a motherboard that can support up to 2TB of RAM.

Attached to these head units, externally, are one or more JBOD chassis filled with hard drives. JBOD stands for “just a bunch of disks” and they are typically 4U chassis containing 45 or 60 drives that attach back to the head unit with SAS cables.

rsync.net has no firewalls and no routers. In each location we connect to our IP provider with a dumb, unmanaged switch.

This might seem odd, but consider: if an rsync.net storage array is a FreeBSD system running only OpenSSH, what would the firewall be ? It would be another FreeBSD system with only port 22 open. That would introduce more failure modes, fragility and complexity without gaining any security.