Issu Methods For A Compatible Version; Issu Method For An Incompatible Version; Issu Command Series - HP 5920 series Fundamentals Configuration Manual

ISSU methods for a compatible version

The following are ISSU methods for a compatible version:
• Incremental upgrade:
An incremental upgrade analyzes the differences between the new and old software versions and
upgrades only the different parts. An incremental upgrade takes the least time and imposes the
least effect on the device.
Incremental upgrade methods include:
Service-level incremental upgrade—This method involves only the upgraded service modules.
The other service modules can provide services during the upgrade.
File-level incremental upgrade—This method involves only hidden system program files. The
system can operate and provide services during the upgrade.
• ISSU reboot:
An ISSU reboot upgrade saves the current system information (including the operation data,
configuration data, hardware data, and status information) to memory and uses the new software
to reboot the CPU. During an ISSU reboot upgrade, the data plane of the system keeps forwarding
packets. After startup, the CPU continues to provide services on the basis of the saved system
information. For services that require regular protocol message exchanges to maintain
connections, this method starts protocol agents to meet the requirements.
Compared with an incremental upgrade, an ISSU reboot upgrade affects all modules that use the
CPU and takes a longer time.
Reboot:
•
This method reboots member devices to load the new software.
When the IRF fabric has more than one member and both the master and the subordinate members
need to be rebooted for the upgrade, upgrade subordinate members first and make sure one
upgraded subordinate member becomes the master after a switchover to implement in-service
upgrade. When the IRF fabric has only one member, service interruption is unavoidable during the
upgrade.

ISSU method for an incompatible version

Only one method is available for an ISSU to an incompatible version: incompatible upgrade. This
method reboots the device to load the new software. To reduce service interruption during the upgrade,
implement hardware redundancy.

ISSU command series

The device supports the following ISSU command series:
install command series.
•
issu command series.
•
To install or uninstall patches, you can use only the install command series. To perform the other ISSU
tasks, you can use either of the install command series or the issu command series. HP recommends that
you use the issu command series.
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