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Set Up a Multipath Configuration for SAN Storage

Setting up a multipath configuration is required for a CA User Activity Reporting Module system installed on a RAID system that is to use SAN storage. Physical disks on the SAN are partitioned into logical storage spaces named logical unit numbers (LUNs).

Set up a multipath configuration for SAN storage

  1. Log on to the CA User Activity Reporting Module appliance and su to root.
  2. (Optional) Do a directory listing of /dev/mapper to view the state of the configuration before setting up multipathing and logical volumes. Results resemble the following:
    drwxr-xr-x  2 root root     120 Jun 18 12:09 .
    drwxr-xr-x 11 root root    3540 Jun 18 16:09 ..
    crw-------  1 root root  10, 63 Jun 18 12:09 control
    brw-rw----  1 root disk 253,  0 Jun 18 16:09 VolGroup00-LogVol00
    brw-rw----  1 root disk 253,  2 Jun 18 12:09 VolGroup00-LogVol01
    brw-rw----  1 root disk 253,  1 Jun 18 16:09 VolGroup00-LogVol02
    
  3. Open the .../etc/multipath.conf file for edit and proceed as follows:
    1. Add the following section under "device {" for each LUN provided by the SAN administrator:
      device {
      
      vendor                 "NETAPP"  
      product                "LUN"
      path_grouping_policy   multibus
      features               "1 queue_if_no_path"
      path_checker           readsector0 
      path_selector          "round-robin 0"
      failback               immediate
      no_path_retry          queue
           }
      
    2. Uncomment the 'blacklist' section for all devices. The blacklist section enables multipathing on default devices.
      blacklist {
      
      devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
      devnode "^hd[a-z]"
      devnode "^cciss!c[0-9]d[0-9]*"
      
      }
      
    3. Save and close the multipath.conf file.
  4. Verify that Multipath is turned on and that the LUNs are listed by running the following:
    multipath -l
    

    Note: Paths display as ‘mpath0’ and ‘mpath1’. If the LUNs are not shown, reboot and run multipath again.

  5. View the available drives.
    fdisk -l
    
  6. List the available partitions and verify that 'mpath0' and 'mpath1' are listed.
    ls -la /dev/mapper
    
  7. Map the first partition as follows:
    kpartx -a /dev/mapper/mpath0
    
  8. Map the second partition as follows:
    kpartx -a /dev/mapper/mpath1