Volumes Question

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Currently I got 2 servers and  connecto both 2 SAN storage (configure 4 volumes on each SAN storage).

And also I am going to build a cluster on the servers.

But before build the cluster I need to fix this problem. How can I make this duplicated volumes in to 2 single volume. Both servers has same problem.


[root@seerver1 ~]# cat /proc/partitions

major minor  #blocks  name


   8        0   71652960 sda

   8        1     512000 sda1

   8        2   71139328 sda2

   8       16     976560 sdb                    <=LUN

   8       32  117187472 sdc                <=Mysql

   8       48   97656240 sdd                 <=FSMSC

   8       64   48828112 sde                 <=Tomcat

   8       80     976560 sdf                     <=LUN

   8       96  117187472 sdg                <=Mysql

   8      112   97656240 sdh                <=FSMSC

   8      128   48828112 sdi                 <=Tomcat

253        0   52428800 dm-0

253        1    2064384 dm-1





Hi Danny,


I do not see any problem here.


Are you talking about the two devices sdb and sdf seen for a single LUN. These are because there are two paths from the server to the storage. Could you please confirm this from your storage team as well ? In order to use this LUN, you will need some kind of multipathing solution. For example DM-Multipath in RHEL.


This will create a logical device mpathX that needs to be used.


For more details please see






- Nitin


Hi mate:


I know it isn’t something went wrong.

Because it seen duplicate it was come 2 SAN storage.

Is there a way to mirror duplicate volumes in to 1 volume. Before I do start the cluster build?




Trying to parse what you're saying. Are you saying that each of the above /dev/sdX devices is a unique LUN and not two paths to the same LUN (e.g., sdc:Mysql and sdg:Mysql are actually two, discreetly-presented LUNs from your SAN)? 


  • If the pairs of /dev/sdX devices are actually pairs of discreet LUNs, you should be able to just mirror each pair in LVM
  • If the pairs of /dev/sdX devices are actually path-pairs to a single LUN, then you need something like DM-multipath, Veritas Volume Manager, PowerPath, etc. to coalesce the paths into a single meta-device.