Exalogic: How to Switch ZFS Storage Heads Cluster Configuration From Active-Active to Active-Passive (Recommended)

Asset ID:	1-71-1929373.1
Update Date:	2018-01-22
Keywords:

Solution Type Technical Instruction Sure

Solution 1929373.1 : Exalogic: How to Switch ZFS Storage Heads Cluster Configuration From Active-Active to Active-Passive (Recommended)

Applies to:

Oracle Exalogic Elastic Cloud Software - Version 2.0.0.0.0 and later
Oracle Exalogic Elastic Cloud X2-2 Hardware - Version X2 to X2 [Release X2]
Information in this document applies to any platform.

Goal

In Exalogic rack, in some cases ZFS heads part rack end up in active-active configuration instead of active-passive configuration which is recommended.

Following is the output of "configuration cluster show" command in ZFS CLI from both the heads. From below output you can see both the heads are Active.

elorl01sn01-adm:> configuration cluster show
Properties:
                         state = AKCS_CLUSTERED
                   description = Active
                      peer_asn = 4e4f8687-eb9c-4f38-e227-d08391b63100
                 peer_hostname = elorl01sn02-adm
                    peer_state = AKCS_CLUSTERED
              peer_description = Active

elorl01sn02-adm:> configuration cluster show
Properties:
                         state = AKCS_CLUSTERED
                   description = Active
                      peer_asn = e7925012-bc67-c25b-f1e4-e8ea179e2f07
                 peer_hostname = elorl01sn01-adm
                    peer_state = AKCS_CLUSTERED
              peer_description = Active

Active-Active it not supported and not recommended for Exalogic. We have to switch ZFS heads part of Exalogic rack to Active-Passive configuration.

Solution

Follow below steps in order to switch ZFS heads part of Exalogic rack to Active-Passive configuration:

NOTE: Following procedure does not cause outages or issues. Because we are not rebooting the head which is owning the Pool.

Check the head that is handling the shares and which is owner of the pool. For doing this connect to ZFS Storage BUI Console and go to Configuration-> CLUSTER. Here we can see which server is the owner of the pool.

Following is ZFS BUI console screenshot for reference. From below screenshot you can see that SN02 is the owner of the pool.
Connect to the ZFS Console of Storage head that is the owner of the pool. Click on TAKEOVER from the ZFS BUI console under Configuration-> CLUSTER. This will move the cluster configuration to Active - Ready (which means Active-Passive).

Following is the output of "configuration cluster show" command in ZFS CLI from both the heads after the takeover. From below output you can see SN02 is now in active state and SN01 is in Ready state which means it is passive.

elorl01sn01-adm:> configuration cluster show
Properties:
                         state = AKCS_STRIPPED
                   description = Ready (waiting for failback)
                      peer_asn = 4e4f8687-eb9c-4f38-e227-d08391b63100
                 peer_hostname = elorl01sn02-adm
                    peer_state = AKCS_OWNER
              peer_description = Active (takeover completed)

elorl01sn02-adm:> configuration cluster show
Properties:
                         state = AKCS_OWNER
                   description = Active (takeover completed)
                      peer_asn = e7925012-bc67-c25b-f1e4-e8ea179e2f07
                 peer_hostname = elorl01sn01-adm
                    peer_state = AKCS_STRIPPED
              peer_description = Ready (waiting for failback)

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