Grey Blog: Very good information. I downloaded globalSAN iscsi and I could not find any documentation where the app launcher is!! I use freeNAS 0.70. It now (did not in the past) allow time machine backups on both AFP, SMB,NFS, ZFS. Although worth noting that AFP is twice as fast as a protocol with OSX as any mentioned, even i-scsi. I do have a question, remote formatting is allowed on the host machine? Not an issue with me though using freenas.
I do have Solaris 5.10 on a PC but doing this sort of thing is way too much of an education for me. Again thank you! Glad you liked it. As you can see in the screenshots, GlobalSAN has no app launcher: it just uses a custom preference pane that you can access by launching the System Preferences application.
Popular Alternatives to globalSAN for Mac, Software as a Service (SaaS), Windows. We are pleased to announce that our globalSAN iSCSI initiator for OS X is.
From there, you'll be able to register your iSCSI targets, mount them and unmount them. I'm aware that Time Machine can use unsupported volume types such as NFS and CIFS: if Time Machine supported NFS, it would be an incredibly easy configuration to setup and go. However, since I prefer having it use a supported volume type, I've decided to rely on publishing a ZFS Volume as an iSCSI target.
I recognize that it's a more complex setup but, as far as I can tell, it's worth the effort. When you mount an iSCSI volume with the GlobalSAN initiator, Mac OS X will see it as a local drive: thus you'll be able to use Disk Utilities to format it with HFS+.
In fact, that's what Time Machine actually does when using such a volume for the first time. I'm not suggesting you drop FreeNAS, of course, however, if you're at least familiar with a ZFS-enabled Solaris, I encourage you try it to build your storage server. I greatly appreciate ZFS features, its clean administrative model and its ease of use.
You might also want to try OpenIndiana, Nexenta and NexentaStor as alternatives. You're welcome, Grey.
Thanks Andrew, you're absolutely right. It seems that, as soon as the GlobalSAN initiator had some success, they changed the licensing model.
I never updated this post, and it's good you posted your comment. Needless to say, I'm not going to pay that license for such a home-user scenario. It's a pity, because it was great to have that possibility. Instead, since Lion broke the last free version of the GlobalSAN initiator, I'm performing few Time Machine backups on an external drive and switched to a heavier use of rsync against the same ZFS datasets, published using NFS. 
I made a small Cocoa GUI for rsync, which is not production-ready yet, but I'll surely post about it in the near future. Hello, Just followed your guide (at least parts of it), and got everything up and running.
The main issue I had in the end was the inability to update the size of the final formatted disk. Resizing the ZFS volume and LU wasn't very difficult, and a simple disconnect/reconnect of the iSCSI target updated the size of the disk (iSCSI disk) on my mac. From here I couldn't get the formatted disk to update in size, no matter what i tried.