Tuesday 22 November 2011

Multipath in HP UX


Multipath:

A simple example would be a SCSI disk connected to two SCSI controllers on the same computer or a disk connected to two Fibre Channel ports. Should one controller, port or switch fail, the operating system can route I/O through the remaining controller transparently to the application, with no changes visible to the applications, other than perhaps incremental latency.

Features of Multipath:

    * Dynamic load balancing
    * Traffic shaping
    * Automatic path management
    * Dynamic reconfiguration

How to find multipath on hp ux ??

1.pvlinks

   # strings /etc/lvmtab
   # vgdisplay -v vgname

2.Native Multipathing (11.31) (agile device name)

  # ioscan -m dsf h/w address
   
    Examble : ioscan -m dsf/dev/rdisk/disk586
              Persistent DSF      Legacy DSF(s)
          =============================================
              /dev/rdisk/disk586  /dev/rdsk/c15t0d0
                                  /dev/rdsk/c16t0d0


  # scsimgr -D lun_map (which will give the number of paths to that lun)

  # ioscan -kfnNC  (will show the persistent device file in 11.31)

  # evainfo (EVA) and xpinfo (XP) - commands will show the multipaths for luns.

1 comment:

  1. How to identify if different device file names refer to the same LUN on HP-UX 11.23 when multipathing is configured?

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