This article describes how to rescan QLogic Host Bus Adapter (HBA) for new Logical Unit Numbers (LUNs), and query the HBA or ISCSI in XenServer.

Requirements

• XenServer 8.2 CU1 or later

• Basic Command Line Interface skills

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Instructions

Repeat the following steps on each server in the pool:

1. Run the following command to find the scsi_host directory. To be able to send the command for rescan you must find the correct scsi_host directory:

   # cat /proc/scsi/scsi

   Host: scsi3 Channel: 00 Id: 00 Lun: 01
     Vendor: NETAPP   Model: LUN              Rev: 0.2
     Type:   Direct-Access                    ANSI SCSI revision: 04
   Host: scsi2 Channel: 00 Id: 00 Lun: 01
     Vendor: NETAPP   Model: LUN              Rev: 0.2
     Type:   Direct-Access                    ANSI SCSI revision: 04
   

   You can see that that the HBA driver is mapped to host scsi3 and scsi2, which XenServer translates to host2 and host3.
   Note: Servers in the pool might be having different scsi_host numbers.

2. Run the following command to view the current LUN count:
   # scli -t

   Note: If "scli" is not in the path, you can find it at /opt/QLogic_Corporation/QConvergeConsoleCLI/scli

3. Send the rescan command and check the LUN count update:

   # echo "- - -" > /sys/class/scsi_host/host2/scan
   # scli –t
   
   # echo “- - -“ > /sys/class/scsi_host/host3/scan
   # scli –t

4. Run the following command to view the LUN details:
   # scli –l 0
   # scli –l 1

5. Run the corresponding commands from the following list, to display HBA and SCSI details using systool:

   • To examine some simple information about the Fibre Channel HBAs in a unit:
     # systool -c fc_host –v

   • To look at verbose information regarding the SCSI adapters present on a system:
     # systool -c scsi_host –v

   • To see what Fibre Channel devices are connected to the Fibre Channel HBA cards:
     # systool -c fc_remote_ports -v –d

   • For Fibre Channel transport information:
     # systool -c fc_transport –v

   • For information on SCSI disks connected to a system:
     # systool -c scsi_disk –v

   • To examine more disk information including which hosts are connected to which disks:
     # systool -b scsi –v

   • Use the sg_map command to view more information about the SCSI map:
     # sg_map –x

   • To obtain driver information, including version numbers and active parameters:
     For QLogic HBAs:
     # systool -m qla2xxx –v
     For Emulex HBAs:
     # systool -m lpfc –v

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This article describes how to rescan the QLogic Host Bus Adapter for New Logical Unit Numbers in XenServer

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