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Adding a LUN to servers without rebooting

Below a concreate example of adding luns to a linux server without being forced to reboot it:

1 Install the right driver for the HBA

The driver depends on the HBA. don't use the generic one user by the OS. In our case, the HBA is qlogic2340. it's driver can be easilly downloaded from the vendor website.

2 LUN generation and masking

this opertation is done directly on the disk array.

3 Visbility of the LUNs to the HBA

To make sure that the HBA can see the newly created LUNs, we can use it's command line utility, as follows:

   
scli 
scli –l 0
scli -l 1

This will scan all the FC ports. this gives:

Product Vendor             : DGC     
Product ID                 : RAID 5          
Product Revision           : 0219
LUN                        : 12
Size                       : 1.00 GB
Type                       : SBC-2 Direct access block device (e.g., magnetic disk)
WWULN                      : 60-06-01-60-4D-40-18-00-40-20-84-A4-2B-F6-DA-11

4 SCSI mapping and Powerpath links

 echo "scsi-qlascan" >>/proc/scsi/qla2xxx/2
 echo "scsi-qlascan" >>/proc/scsi/qla2xxx/1
 echo "scsi add-single-device 1 0 0 12">> /proc/scsi/scsi
 echo "scsi add-single-device 2 0 0 12">> /proc/scsi/scsi
 echo "scsi add-single-device 1 0 1 12">> /proc/scsi/scsi
 echo "scsi add-single-device 2 0 1 12">> /proc/scsi/scsi

Note: scsi add-single-device A B C D, where A=host , B=Channel C=ID D=LUN

powermt display dev=all

It gives:

Pseudo name=emcpowerk

CLARiiON ID=4Z0W32J [ecul2007_NURUN]
Logical device ID=600601604D401800402084A42BF6DA11 [LUN 12]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP B, current=SP B
 ==============================================================================  
 ---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats ---
 ### HW Path                 I/O Paths    Interf.   Mode    State  Q-IOs Errors
 ==============================================================================
 1 qla2xxx                   sdaz      SP B1     active  alive      0      0
 2 qla2xxx                   sdba      SP B0     active  alive      0      0
 1 qla2xxx                   sdbb      SP A0     active  alive      0      0
 2 qla2xxx                   sdbc      SP A1     active  alive      0      0