1. What is NetApp Cluster-Failover Giveback?Concept:If one of the NetApp Filer (HA Pair*) fails for any reason, the other head will take over the failedheads disks and network connections. Once the failed head has recovered and is booting, it willpause and wait for the other head to give back its resources. The operational head must be told togive back the resources, after which the peers will sync up and take over their normal operations.Determining if the heads are in a failover state:Systems should receive an e-mail from the remaining head when it takes over from the failed head.Depending on the configuration, the subject or body will say:CLUSTER TAKEOVER COMPLETE AUTOMATIC on netapp_head2You may also see this message on the survival node console.This means that netapp_head2 is up and has taken over operations for its peer.If you SSH in to netapp_head2, the prompt should read:netapp_head2(takeover)>To indicate that it has taken over the partner.You can gather more information about the cluster failover statuswith the following command:netapp_head2(takeover)> cf monitorcurrent time: 03Nov2012 10:28:48TAKEOVER 00:20:01, partner netapp_head1, cluster monitor enabledAs you can see, it is in a TAKEOVER state for partner netapp_head1, and has been for just over 20minutes.
2. Steps to perform before requesting a giveback:Before requesting a giveback from the operational head, you should ensure that the failed head isready to come back up. You can do this by accessing the downed nodes console via serialconnection or RLM/SP. The console should be blank. Pressing Enter should yield the following text:Waiting for giveback... (Press Ctrl-C to abort wait)Do NOT press Ctrl-C, as this will leave the host in a very confused state.Performing a cluster-failover giveback:On the operational heads console, run the following command:netapp_head2(takeover)> cf givebackAfter a short delay, both heads should start spewing information and sending alerts as the downedhead boots, connects to its disks, and resumes network services.To confirm that the giveback has been completed, run the followingcommand:netapp_head2 > cf monitorcurrent time: 03Nov2012 10:32:42UP 00:24:22, partner netapp_head1, cluster monitor enabledVIA Interconnect is up (link 0 up, link 1 up), takeover capability on-linepartner update TAKEOVER_ENABLED (03Nov2012 11:38:41)This indicates that the partner is up, and has been for just over 24 minutes. This head is ready totakeover the partner again, if need be.
3. What is HA Pair?HA pair consists of a pair of matching FAS or V-Series storage controllers (local node and partnernode). Each node is connected to its partner’s disk shelves.The Data ONTAP and firmware versions on the two nodes must be identical. Similarly, theinterconnect adapters on the nodes must be identical and must be configured with the samefirmware version. Also, the interconnect adapters must be connected properly by the appropriateinterconnect cables. HA pairs provide fault tolerance and enable the performance of nondisruptiveupgrades and maintenance.On the side note, NetApps cluster-mode configuration is also based on HA Pair. In other words, thebasic building blocks are still the standard FAS or V-Series HA pairs that we all are so familiar with. Acluster includes multiple HA pairs. The HA pairs are joined by a namespace that is shared over aninternal network. The network is referred to as "the cluster network."-Prepared firstname.lastname@example.org