We have been using iSCSI and B2D for over a year successfully. The only caveat is that we have to uncheck the "Auto Detect Settings" and check the "Buffered Reads" and "Buffered Writes" when setting up the B2D folder.
However, when we select the "Allocate the maximum size for backup-to-disk files" box, the backup job stays queued indefinitely, and the event log fills up with eventid 33808's.
It doesn't seem to matter what size of file I specify. 4GB, 2GB, 1GB, even 128MB fails. I've also tried this on different partition sizes (200GB on a 2TB LUN as well as 150GB on a 150GB LUN).
This article (http://seer.entsupport.symantec.com/docs/304959.htm) is pretty close to what we are experiencing. However, once we choose to pre-allocate the files, it fails.
If the B2D folder is created on a local (non-iSCSI) drive, the job runs fine.
