In mid-August, the first commercially available ZFS cloud replication target became available at rsync.net. Who cares, right? As the service itself states, "If you're not sure what this means, our product is Not For You."
Of course, this product is for someone—and to those would-be users, this really will matter. Fully appreciating the new rsync.net (spoiler alert: it's pretty impressive!) means first having a grasp on basic data transfer technologies. And while ZFS replication techniques are burgeoning today, you must actually begin by examining the technology that ZFS is slowly supplanting.
A love affair with rsync
Revisiting a first love of any kind makes for a romantic trip down memory lane, and that's what revisiting rsync—as in "rsync.net"—feels like for me. It's hard to write an article that's inevitably going to end up trashing the tool, because I've been wildly in love with it for more than 15 years. Andrew Tridgell (of Samba fame) first announced rsync publicly in June of 1996. He used it for three chapters of his PhD thesis three years later, about the time that I discovered and began enthusiastically using it. For what it's worth, the earliest record of my professional involvement with major open source tools—at least that I've discovered—is my activity on the rsync mailing list in the early 2000s.