IBM DS8000 manual Adding FC disks dynamically, Example A-12 Sample /etc/modules.conf

Example: A-12 Sample /etc/modules.conf

scsi_hostadapter aic7xxx scsi_hostadapter1 aic7xxx scsi_hostadapter2 qla2300 scsi_hostadapter3 qla2300 options scsi_mod max_scsi_luns=128

Adding FC disks dynamically

The commonly used way to discover newly attached DS8000 volumes is to unload and reload the Fibre Channel HBA driver. However, this action is disruptive to all applications that use Fibre Channel attached disks on this particular host.

A Linux system can recognize newly attached LUNs without unloading the FC HBA driver. The procedure slightly differs depending on the installed FC HBAs.

In case of QLogic HBAs issue the command:

echo "scsi-qlascan" > /proc/scsi/qla2300/<adapter-instance>

With Emulex HBAs, issue the command:

sh force_lpfc_scan.sh "lpfc<adapter-instance>"

This script is not part of the regular device driver package and must be downloaded separately:

http://www.emulex.com/ts/downloads/linuxfc/rel/201g/force_lpfc_scan.sh

It requires the tool dfc to be installed under /usr/sbin/lpfc.

In both cases the command must be issued for each installed HBA, with the <adapter-instance> being the SCSI instance number of the HBA.

After the FC HBAs re-scan the fabric, you can make the new devices available to the system with the command:

echo "scsi add-single-device s c t l" > /proc/scsi/scsi

The quadruple s c t l is the physical address of the device:

￿s is the SCSI instance of the FC HBA

￿c is the channel (in our case always 0)

￿t is the target address (usually 0, except if a volume is seen by a HBA more than once)

￿l is the LUN

The new volumes are added after the already existing ones. The following examples illustrate this. Example A-13shows the original disk assignment as it existed since the last system start.

Example: A-13 SCSi disks attached at system start time

/dev/sda - internal SCSI disk

/dev/sdb - 1st DS8000 volume, seen by HBA 0 /dev/sdc - 2nd DS8000 volume, seen by HBA 0 /dev/sdd - 1st DS8000 volume, seen by HBA 1 /dev/sde - 2nd DS8000 volume, seen by HBA 1

362DS8000 Series: Concepts and Architecture