After adding new SAN LUNs, multipath devices are not showing up in Device Mapper Multipath?

Solution Verified - Updated -

Issue

Please note that performing issue_lip is not recommended to scan the newly added devices on existing storage ports. This operation performs a Loop Initialization Protocol (LIP), scans the interconnect, and causes the SCSI layer to be updated to reflect the devices currently on the bus. Essentially, an LIP is a bus reset, and causes device addition and removal. To scan the devices without affecting the existing paths, use How to rescan the SCSI bus to add or remove a SCSI device without rebooting the computer. The methods of detecting new luns, as outlined in the aforementioned document, should be tried before attempting a LIP. A LIP will result in all in-flight IO to being lost and can result in significant error recovery actions which can adversely impact system performance.

  • Have 17 LUNs newly made available to the server, can see those disks from fdisk -l. However, multipath -ll does not show paths to those LUNs. Following are the steps performed so far:

    1. Rescan Fiber Channel by running:

    # echo "1" > /sys/class/fc_host/host3/issue_lip
    # echo "1" > /sys/class/fc_host/host4/issue_lip
    

    2. Reload multipath configuration:

    # service multipathd reload
    

    3. Check new devices with fdisk -l
    4. multipath -ll

Environment

  • Red Hat Enterprise Linux 6
    • Device Mapper Multipath(DM Multipath)
  • Fibre Channel Storage

Subscriber exclusive content

A Red Hat subscription provides unlimited access to our knowledgebase of over 48,000 articles and solutions.

Current Customers and Partners

Log in for full access

Log In