Disk marked UNAVAIL / "cannot open" in zpool

Sun Managers,

I am running into an issue with a Sun X4200 M2 running Solaris 10 x86 11/06.
We had to reboot the server because it was unresponsive this morning, and when
it came back online, one FC device in one of our zfs pools shows up as
unavailable. This zfs pool is a striped pool and is naturally unhealthy due to
this state. zpool status -x reports the drive as UNAVAIL due to "cannot
open".

On the SAN side, everything looks healthy. This device shows up in iostat,
shows up with both paths as ONLINE using luxadm display, and is shown in
format (although it's "description" differs from three other LUNs from the
same SAN; its LUN shows as NEXSAN-SATABeast-Gw66 cyl 17821 alt 2 hd 255 sec
945 versus an identical, healthy LUN showing NEXSAN-SATABeast-Gw66-7.28TB).
Areas that look like trouble are the fact that format doesn't see a label,
prtvtoc reports: Unable to read Disk geometry errno = 0x5, prtdiag is missing
a "dev_link" entry for d0 alone like the healthy devices (it has entries for
d0s0 through d0s15 and d0p0 through d0p4). A link is also missing in /dev/dsk
& /dev/rdsk for that same d0 entry. devfsadm removed these entries when run
earlier, as shown:

devfsadm[6182]: verbose: removing file:
/dev/dsk/c5t6000402002FC424F6CF5318F00000000d0
devfsadm[6182]: verbose: symlink
/dev/dsk/c5t6000402002FC424F6CF5318F00000000d0s7 ->
../../devices/scsi_vhci/disk@g6000402002fc424f6cf5318f00000000:h
devfsadm[6182]: verbose: removing file:
/dev/rdsk/c5t6000402002FC424F6CF5318F00000000d0
devfsadm[6182]: verbose: symlink
/dev/rdsk/c5t6000402002FC424F6CF5318F00000000d0s7 ->
../../devices/scsi_vhci/disk@g6000402002fc424f6cf5318f00000000:h,raw

I booted to single user mode to attempt to use verify and/or backup on the
device and they only returned the "disk may be in use" warning.

Any assistance that can be provided would be greatly appreciated. I will
happily summarize when the issue is resolved.

Thanks,

Tim