I have some Medea FibreBlock RAID arrays that can operate with either a
512 byte or 2K byte sector size. The arrays consist of five IDE disks
and an embedded controller and look like a single disk on the FC bus.

Because inbound 2K requests can be mapped exactly to five 512-byte
requests to each of the component disks in the RAID set, the arrays are
somewhat more performant when in 2K sector mode on the FC side. This
seems to _mostly_ work with Irix; I can use fx to label and partition
the disks, the resulting label correctly shows a 2K sector size, and I
can use dd bs=2048 to read and write the disks via the raw partition.

If I use dd with a 512-byte blocksize, in this mode, it dumps core.

If I use mkfs_xfs... uh oh. It correctly detects that the sector size
is 2K, but then at some point attempts to do a write shorter than 2K
(this is just an inference based on what makes dd dump core) and dumps
core.

I'm sure Irix must support SCSI/FC disks with large sector sizes. What's
going on here?

The OS is Irix 6.5.17; the FibreBlocks are on a QLA2300 controller and
work perfectly (albeit not quite as fast as I might like) when set up
for 512-byte sectors.

--
Thor Lancelot Simon tls@rek.tjls.com
But as he knew no bad language, he had called him all the names of common
objects that he could think of, and had screamed: "You lamp! You towel! You
plate!" and so on. --Sigmund Freud