Eliminating Single Points Of Failure With Ha Pair Configurations - IBM N series Hardware Manual

5. Give back the partner node by entering the following command:
cf giveback
The local node releases the partner node, which reboots and resumes normal operation.
The following message is displayed on the console when the process is complete:
giveback completed
6. Proceed as shown in Table 7-3, depending on whether you received the message that
giveback was completed successfully.
Table 7-3 Takeover and giveback messages
If takeover and giveback
Is completed successfully
Fails

7.3.8 Eliminating single points of failure with HA pair configurations

Table 7-4 lists the ways that the use of HA pair configurations helps you to avoid SPOFs in
various hardware components.
Table 7-4 Avoiding SPOFs by using HA pair configurations
Hardware
component
Non-HA
pair
IBM System Storage Yes
N series storage
system
NVRAM Yes
Processor fan Yes
Multiple NICs with No
VIFS (virtual
interfaces)
Single NIC Yes
FC-AL card Yes
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IBM System Storage N series Hardware Guide
Then
Repeat steps 2 - 5 on the partner node.
Attempt to correct the takeover or giveback failure.
SPOF SPOF eliminated
HA pair
No If a storage system fails, cluster failover automatically fails
over to its partner storage system and serves data from the
takeover system.
No If an NVRAM adapter fails, cluster failover automatically fails
over to its partner storage system and serves data from the
takeover storage system.
No If the processor fan fails, the node gracefully shuts down.
Cluster failover automatically fails over to its partner storage
system and serves data from the takeover storage system.
No If one of the networking links fails, the networking traffic is
automatically sent over the remaining networking links on the
storage system. No failover is needed in this situation.
If all NICs fail, you can start failover to a partner storage
system and serve data from the takeover storage system.
Tip: Always use multiple NICs with VIFS to improve
networking availability for both single storage systems and
HA pair storage systems.
No If a NIC fails, you can start a failover to its partner storage
system and serve data from the takeover storage system.
No If an FC-AL card for the primary loop fails, the partner node
attempts a failover at the time of failure.
If the FC-AL card for the secondary loop fails, the failover
capability is disabled. However, both storage systems
continue to serve data to their respective applications and
users, with no effect or delay.