Adding metadata LUNs to SAN File System

This topic describes how to add metadata LUNs to SAN File System.

Prerequisites

Attention: For non-disruptive addition and expansion of volumes, the client operating systems must support on-line replacement and on-line insertion (OLR/OLI) capability. If the clients do not have OLI/OLR capability, then the clients will not be able to discover the newly added LUNS without disruption. In this case, you must reboot the client machines to discover the LUNs.

Context

This task describes how to add metadata LUNs without having to stop the cluster, stop and restart each metadata server, and start the cluster.

Steps

  1. Assign the host bus adapters (HBAs) of the new storage systems (for example, IBM® Enterprise Storage System (ESS)) to the appropriate zones, as required.
  2. Map the new LUNs to the metadata server engines according to LUN restrictions, limitations, and considerations for mapping.
  3. On each metadata server engine, map the new devices by performing the following steps:
    1. Force the HBA driver (QLogic or equivalent) to rescan the fabric. For example, if you are using the QLogic driver, enter these commands at the system prompt:
      echo scsi-qlascan >/proc/scsi/qla2300/2
      echo scsi-qlascan >/proc/scsi/qla2300/3
    2. View the target ID and the LUN for all LUNs that were added by entering the following command at the system prompt:
      more /proc/scsi/qla2300/2
    3. Record the ID LUN combination for any LUN that is not yet registered with the operating system.
    4. For each controller number (2 and 3 are the controller numbers for the QLogic 2342 ports) and ID LUN combination, enter this command at the system prompt:
      echo "scsi add-single-device controller 0 ID LUN">/proc/scsi/scsi
    5. Force the Subsystem Device Driver (SDD), or equivalent driver, to rescan and map the new devices. For SDD, enter the following command at the system prompt:
      /usr/sbin/cfgvpath

Parent topic: Managing volumes and LUNs

Related reference
mkvol

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