Q:

What does "no device" mean when running iostat -En

We presume to have a faulty cable that connects the SAN to a direct I/O LDOM. This is a snippet of the error when running iostat -En
   c5t60060E8007C50E000030C50E00001067d0 Soft Errors: 0 Hard Errors: 696633 Transport Errors: 704386
Vendor: HITACHI  Product: OPEN-V           Revision: 8001 Serial No: 504463
Size: 214.75GB <214748364800 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 6 Recoverable: 0
Illegal Request: 1 Predictive Failure Analysis: 0

What does No Device: 6 mean here?

A:

A search  through the Illumos fiber-channel device code for ENODEV shows 13 uses of ENODEV in the source code that originated as OpenSolaris.
Of those instances, I suspect this is the one most likely to cause your "No device" errors:
pd = fctl_hold_remote_port_by_pwwn(port, &pwwn);
if (pd == NULL) {
    fcio->fcio_errno = FC_BADDEV;
    return (ENODEV);
}

That code is in the fp_fcio_login() function, where the code appears to be trying to login to a remote WWN.  It seems appropriate to assume a bad cable could prevent that from happening.  Note that fiber-channel error code is FC_BADDEV, which also seems appropriate for a bad cable.
In short, a review of the source code indicates that ENODEV errors are consistent a bad cable.  
You can use dTrace to more closely identify the association if necessary.  Given that both hard and transport errors occur about 5 or 6 orders of magnitude more frequently, IMO that effort isn't necessary until the ENODEV errors occur after the other errors are addressed and no longer occur.

