First of all, take a long breath and a seat. Let’s go over this whole story step by step and I’ll explain to you why, yes, it may become incompatible, and no, it won’t stay that way for long.
Let’s start at the fundamentals. Despite its shiny outside, a DroboFS is not much more than a dedicated Linux box with some fancy data redundancy layer beneath the Linux operating system. What does that mean? That besides the said fancy redundancy technology, there is not one feature from the DroboFS that is not coming from Linux. Indeed, if we take a look at the software running on a DroboFS, we’ll see:
A Drobo-specific version of Samba, which provides support for Windows file sharing (a.k.a. SMB). It is actually a crippled version, since it does not allow the FS to behave as a SMB client, just as a server.
A Drobo-specific version of NFS, which provides support for the most common Linux file sharing protocol. Also kind of crippled, since it is not the high performance kernel version. Also here the FS is not able to act as a client, just as a server.
A Drobo-specific version of netatalk. Netatalk is the Linux implementation of the Apple file sharing protocol (AFP). Netatalk offers simple file access, but also TimeMachine support. Again, only as a server.
[/list]*) file sharing here does not mean P2P, but instead the capability of a specific operating systems to make files available in the local network.
So what does it all mean? It means that DRI is not implementing TimeMachine support themselves, but instead are relying on the good work of the guys over at Netatalk to implement TimeMachine functionality. They just take the netatalk source code, compile it for the FS, configure it correctly, and (hopefully) do some heavy testing to make sure it is reliable.
In other words, as soon as the netatalk guys manage to offer support for Lion, I’m pretty sure that a couple of days later we will have a new firmware for the Drobo. And unless Apple decides to be a d*ck about it (i.e. using some kind of encryption or authentication to prevent third parties from reverse-engineering the protocol), you can be sure that it won’t take long for the netatalk guys to implement the “new” TimeMachine protocol. They are pros at reverse engineering that thing.
But all of this seems a bit far fetched in the first place. What will happen to the thousands of Time Capsules out there? Is Apple really going to roll out an update that can potentially break support for old devices? Imagine the following situation: you have one old laptop that cannot go to Lion, and one that can. You use a Time Capsule to backup both. What do you do? Upgrade the Time Capsule firmware to support the Lion laptop, but lose the capacity to backup the old laptop or stop backing up the upgraded laptop?
It seems to me that the only reasonable solution would be for OS X Lion to have some kind of “legacy” or “compatibility” mode. But who knows? Maybe Apple just wants everyone to buy new Time Capsules and get rid of their old Apple hardware…