Get full SCSI Sense out of any command failure

scsi_sense.stp

probe module("scsi_mod").function("scsi_command_normalize_sense") {
        printf("CDB:");
        for (i = 0; i < $cmd->cmd_len; i++) {
                printf(" %02X", $cmd->cmnd[i]);
        }
        printf(" | SENSE:");
        for (i = 0; i < 32; i++) {
                printf(" %02X", $cmd->sense_buffer[i]);
        }
        printf("\n");
}

You can use http://scsi.ev-en.org/ to decode the sense and http://blog.disksurvey.org/knowledge-base/scsi-sense/ to make sense of what it means.