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NAME

na_cf - Controls the takeover and giveback operations of the nodes in a High Availability (HA) pair.

SYNOPSIS

cf [ disable | enable | forcegiveback | forcetakeover [ -df ] | giveback [ -f ] | hw_assist [ status | test stats [ clear ] ] | monitor | partner | status [ -t ] takeover [ -f ] | [ -n ]]

DESCRIPTION

The cf command controls the controller failover monitor, which determines when takeover and giveback operations take place within an HA pair.

OPTIONS

disable
Disables the takeover capability of both nodes in the HA pair.

enable
Enables the takeover capability of both nodes in the HA pair.

forcegiveback
forcegiveback is dangerous and can lead to data corruption; in almost all cases, use cf giveback -f instead.

Forces the live node to give back the resources of the failed node, even though the live node determines that doing so might result in data corruption or cause other severe problems. giveback will refuse to giveback under these conditions. Using the forcegiveback option forces a giveback. When the failed node reboots as a result of a forced giveback, it displays the following message:

partner giveback incomplete, some data may be lost

forcetakeover [-f] forcetakeover is dangerous and can lead to data corruption; in almost all cases, use cf takeover instead.

Forces one node to take over its partner, even though the node detects an error that would otherwise prevent a takeover. For example, normally, if a detached or faulty Infiniband cable between the nodes causes the nodes' NVRAM contents to be unsynchronized, takeover is disabled. However, if you enter the cf forcetakeover command, the node takes over its partner despite the unsynchronized NVRAM contents. This command might cause the node being taken over to lose client data. If you use the -f option, the cf command allows such a forcetakeover to proceed without requiring confirmation by the operator.

forcetakeover -d[f] Forces a node to take over its partner in all cases where a forcetakeover would fail. In addition it will force a takeover even if some partner mailbox disks are inaccessible. It can only be used when cf_remote is licensed.

forcetakeover -d is very dangerous. Not only can it cause data corruption, if not used carefully, it can also lead to a situation where both the node and its partner are operational (split brain). As such, it should only be used as a means of last resort when the takeover and forcetakeover commands are unsuccessful in achieving a takeover. The operator must ensure that the partner node does not become operational at any time while a node is in a takeover mode initiated by the use of this command. In conjunction with RAID mirroring, it can allow recovery from a disaster when the two nodes in the HA pair are located at two distant sites. The use of -f option allows this command to proceed without requiring confirmation by the operator.

giveback [ -f ]
Initiates a giveback of partner resources. If the system ID of the partner has changed while the local node is in takeover mode, the ownership of the partner's disks will be updated to the new system ID while giving back. Once the giveback is complete, the automatic takeover capability is disabled until the partner is rebooted. A giveback fails if outstanding CIFS sessions, active system dump processes, or other node operations make a giveback dangerous or disruptive. If you use the -f option, the cf command allows such a giveback to proceed as long as it would not result in data corruption or node error.

hw_assist [ status | test | stats [ clear ] ] Displays information related to the
hardware-assisted
takeover functionality. Use the cf hw_assist status command to display the hardware-assisted functionality status of the local as well as the partner node. If hardware-assisted status is inactive, the command displays the reason and if possible, a corrective action. Use the cf hw_assist test command to validate the hardwareassisted takeover configuration. An error message is printed if hardwareassisted takeover configuration cannot be validated. Use the cf hw_assist stats command to display the statistics for all hw_assist alerts received by the node. Use cf hw_assist stats clear to clear hardware-assisted functionality statistics.

monitor
Displays the time, the state of the local node and the time spent in this state, the host name of the partner and the state of controller failover monitor (whether enabled or disabled). If the partner has not been taken over currently, the status of the partner and that of the interconnect are displayed and any ongoing giveback or scheduled takeover operations are reported.

partner
Displays the host name of the partner. If the name is unknown, the cf command displays ``partner.''

status
Displays the current status of the local node and the HA pair. If you use the -t option, displays the status of the node as time master or slave.

takeover [ -f ] | [ -n ]
Initiates a takeover of the partner. If you use the -f option, the cf command allows a takeover to proceed even if it will abort a coredump on the other node. This option results in an immediate takeover which does not do a clean shutdown. In case of NDU this can result in a NDU failure.

If you use the -n option, the cf command allows a takeover to proceed even if the partner node was running an incompatible version of Data ONTAP. This is used as part of a nondisruptive upgrade process.

SEE ALSO

na_partner(1)


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