HANA nodes end up having the same LPT values
This document (000020690) is provided subject to the disclaimer at the end of this document.
Environment
SUSE Linux Enterprise Server for SAP Applications 12
Situation
Cluster tries to register the primary node as secondary, and the secondary node as primary.
The reason for it is due to manually switching roles of primary to secondary, and vice versa while cluster is in maintenance.
By that, cluster attributes get outdated, and cluster can not pick up the right roles when removed from maintenance.
Such a situation could be clearly seen using crm_mon -A1 command, where cluster nodes end up having the same LPT values, and hana_***_clone_state have values UNDEFINED, WAITING4PRIM, WAITING4REG
crm_mon -Ar command shows the below output...
# crm_mon -Ar ... Node List: * Online: [ node1 node2 ] ... Node Attributes: * Node: node1: * hana_fu2_clone_state : UNDEFINED ... * lpa_fu2_lpt : 10 * master-rsc_SAPHana_FU2_HDB02 : -9000 * Node: node2: * hana_fu2_clone_state : WAITING4PRIM ... * lpa_fu2_lpt : 10 * master-rsc_SAPHana_FU2_HDB02 : -INFINITY
Resolution
- Put the cluster into maintenance mode (crm maintenance on)
- Start HANA manually on both nodes and ensure replication is working
- Place the HANA master/slave resource in unmanaged mode (crm resource unmanage <resource name>)
- Take the cluster out of maintenance mode (crm maintenance off)
- Give it a few minutes (~3-5 minutes should be fine)
- Put the cluster back into maintenance (crm maintenance on)
- Restart the cluster on the primary and the scondary node (crm cluster restart)
- Remove cluster from maintenance mode (crm maintenance off)
- Cleanup resource failures (crm resource cleanup)
- Resource <rsc_SAPHana_***_**** (resource name)> is started on both nodes, and the roles are respectively 4:P for master and 4:S for secondary Only now it is safe to remove the saphana master/slave resource from unmanged mode (crm resource manage <resource name>)
Cause
When cluster is stopped, SAPHana resource agent will during stop operation set LPT on secondary HANA node to 10. The primary LPT is untouched and should contain the timestamp of primary SAP HANA.
When cluster is started, SAPhana resource agent will during start operation set LPT on secondary HANA node to 10. If secondary changed between cluster stop and start this means that both nodes will effectively have a LPT of 10 and manual intervention will be needed.
Disclaimer
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- Document ID:000020690
- Creation Date: 04-Jul-2022
- Modified Date:05-Jul-2022
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- SUSE Linux Enterprise Server for SAP Applications
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