Do we support a setup for redundancy purpose having two different LUNs on two storage arrays with same WWID.

Solution Verified - Updated -

Issue

  • Is the following method to achieve the redundancy for data is supported?

1. Have two storage arrays, both from of the same model from the same vendor.
2. Configured and assigned one LUN ( with four paths ) from each storage array to the server, OS being RHEL6.
3. Both the LUNs have same WWID as such RHEL6 multipath is detecting the LUN with 8 paths

360002ac0000000000000001600009545 dm-2 3PARdata,VV  
size=1.0T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| |- 3:0:1:1 sde 8:64  active ready running
| |- 2:0:0:1 sda 8:0   active ready running
| |- 3:0:0:1 sdd 8:48  active ready running
| `- 2:0:1:1 sdb 8:16  active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
  |- 3:0:3:1 sdi 8:128 active ghost running
  |- 2:0:3:1 sdg 8:96  active ghost running
  |- 3:0:2:1 sdh 8:112 active ghost running
  `- 2:0:2:1 sdf 8:80  active ghost running

4. First four paths are from Storage array1 and the last four are from storage array2
5. With this setup, replication of the LUN/data will happen from storage1 to storage2
6. During replication, LUN from storage array2 will be in ro mode.

7. After replication, manual failover to LUN from storage2 on storage side will happen such that LUN from storage array2 becomes rw and LUN from array1 becomes ro.
8. During this failover, filesystem on this LUN is going to read-only mode which needs to be avoided.

Is this kind of setup supported for data redundancy.

Environment

  • Red Hat Enterprise Linux
    • Storage arrays with capability to have same WWID for two different LUNs in different storage arrays.
    • DM-Multipath

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