Emulex Lun Scan Script

Algo muy común en servidores Linux es escanear el BUS SCSI para descubrir nuevos discos de la SAN. Para facilitar la labor del administrador, en este caso, el fabricante de tarjetas de fibra proporciona  el siguiente script:

#!/bin/sh
#
#/*******************************************************************
# * This file is part of the Emulex Linux Device Driver for         *
# * Fibre Channel Host Bus Adapters.                                *
# * Copyright (C) 2003-2005 Emulex.  All rights reserved.           *
# * EMULEX and SLI are trademarks of Emulex.                        *
# * www.emulex.com                                                  *
# *                                                                 *
# * This program is free software; you can redistribute it and/or   *
# * modify it under the terms of version 2 of the GNU General       *
# * Public License as published by the Free Software Foundation.    *
# * This program is distributed in the hope that it will be useful. *
# * ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND          *
# * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,  *
# * FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE      *
# * DISCLAIMED, EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD *
# * TO BE LEGALLY INVALID.  See the GNU General Public License for  *
# * more details, a copy of which can be found in the file COPYING  *
# * included with this package.                                     *
# *******************************************************************/
#
# scripts/lun_scan Rev : 1.2
# This script is provided by Emulex to use with its 7.x and 8.x linux device
# drivers for Light Pulse Fibre Channel adapters.
#
# This script performs a scan on either specific lpfc HBAs or on all
# lpfc HBAs.  When scanning an HBA, all discovered targets, and all
# luns will be probed.
#
#
# USAGE: The script is invoked with at least 1 argument. The arguments
# specify either the SCSI Host numbers corresponding to the specific
# lpfc HBA that are to be scanned, or the keyword "all" which indicates
# that all lpfc HBAs are to be scanned.
#
VERSION="1.2"
OS_REV=`uname -r | cut -c1-3`
usage()
{
     echo ""
     echo "Usage: lun_scan [ <#> [<#>] | all ]"
     echo "  where "
     echo "    <#> : is a scsi host number of a specific lpfc HBA that is to"
     echo "          be scanned. More than 1 host number can be specified. "
     echo "    all : indicates that all lpfc HBAs are to be scanned."
     echo ""
     echo "  Example:"
     echo "    lun_scan all  : Scans all lpfc HBAs"
     echo "    lun_scan 2    : Scans the lpfc HBA with scsi host number 2"
     echo "    lun_scan 2 4  : Scans the lpfc HBAs with scsi host number 2 and 4"
     echo ""
     echo "  Warning: Scanning an adapter while performing a tape backup should"
     echo "    be avoided."
     echo ""
}
abort_exit() {
     echo ""
     echo "Error: Cannot find an lpfc HBA instance with scsi host number : $host"
     echo "... Aborting lun_scan."
     echo ""
     exit 2
}
# Validate argument list
if [ $# -eq 0 -o "$1" = "--help" -o "$1" = "-h" ] ; then
 usage
 exit 1
fi
# Get list of lpfc HBAs to scan
hosts=$*;
if [ ${OS_REV} = 2.4 ]; then
 lowhost=0
 ha=`ls /proc/scsi/lpfc/?   2> /dev/null | cut -f5 -d'/'`
 hb=`ls /proc/scsi/lpfc/??  2> /dev/null | cut -f5 -d'/'`
 hc=`ls /proc/scsi/lpfc/??? 2> /dev/null | cut -f5 -d'/'`
 all_hosts="$ha $hb $hc"
 lowhost=`echo $all_hosts | sed "s/ .*//"`
else
 all_hosts=`ls -1 -d /sys/bus/pci/drivers/lpfc/*/host* | sed -e "s/.*host//"`
fi
# If all option is used get all the lpfc host numbers.
if [ "$hosts" == "all" ] ; then
 hosts="$all_hosts"
fi
if [ ${OS_REV} = 2.4 ]; then
 for host in $hosts ; do
     # Convert host number to lpfc instance number.
     instance=`expr $host - $lowhost`
     if [ ! -e /proc/scsi/lpfc/$host ] ; then
         abort_exit
     fi
     echo Scanning lpfc$instance, scsi host number : $host;
     max_lun=256
     targets=`cat /proc/scsi/lpfc/$host | grep 'lpfc*t*' | cut -f2 -d't' | cut -f1 -d' '`
     for target in $targets ; do
         # Convert target ID to decimal from Hex format
         let "dec_target = 0x$target"
         echo "   Scanning Target Id $dec_target..."
         for ((lun=0; lun<$max_lun; lun++)) ; do
             echo "scsi add-single-device $host 0 $dec_target $lun" >/proc/scsi/scsi
         done
     done
 done
else
 for host in $hosts ; do
     if [ ! -e /sys/bus/pci/drivers/lpfc/*/host$host ] ; then
         abort_exit
     fi
     echo Scanning lpfc HBA instance with scsi host number : $host;
     echo '- - -' > /sys/class/scsi_host/host$host/scan
 done
fi
echo ""

Lo que hace el script es comprobar la versión del kernel (2.4 o superior), después comprueba que tarjetas de fibra hay instaladas y por cada una de ella realiza un descubrimiento de los nuevos dispositivos.

Si la asignación en la cabina ha sido correcta podremos ver los nuevos discos de tipo /dev/sdX, ya podremos particionar, formatear y montar el nuevo disco.

Una de las principales ventajas del script es que evitamos tener que reiniciar el servidor para ver nuevos discos de la SAN.