H3C Technologies H3C S12500 Series Switches - Manual (Page 141)

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ISSU implementation
Available ISSU upgrade methods are as follows:
• MPU-based ISSU upgrade, for compatible versions only.
• Member switch-based ISSU upgrade for compatible and partially compatible versions.
• Member switch-based ISSU upgrade for incompatible versions.
• Member switches-based ISSU upgrade, for incompatible versions only.
MPU-based ISSU upgrade (for compatible versions only)
With this method, an IRF fabric is considered as a single switch with one global active MPU, multiple
global standby MPUs, and multiple interface cards. The global active MPU is the active MPU of the
master switch. You can configure and manage the entire IRF fabric at the CLI of the global active MPU.
All MPUs except the active MPU of the master switch are global standby MPUs.
To perform an MPU-based ISSU upgrade:
1. Upgrade the standby MPU of the master when the global active MPU operates.
2. Upgrade each interface card by installing a hotfix, and perform an active and standby switchover,
so the upgraded standby MPU becomes the new global standby MPU.
3. Upgrade the other MPUs one by one.
This method ensures non-stop services or the least service interruption during the ISSU upgrade process
because data and state synchronization during the operation of the IRF fabric provides high consistency
among all MPUs, and the interface cards are upgraded by installing a hotfix without rebooting them.
This method requires that the master have both an active MPU and a standby MPU installed and the new
system software image contain hotfixes for all service cards of the IRF fabric.
During MPU-based ISSU upgrade, no master/subordinate switchover occurs.
This method applies only when the version compatibility check result is compatible.
The upgrade programs for the MPUs and service cards are compressed in the system software image. To
upgrade system software image, use the issu load command.
You can use the display version comp-matrix file upgrading-filename command to display the upgrade
method of each service card if you upgrade the current version to the version specified by the
upgrading-filename argument. If the upgrade method of a service card is displayed as Hotfix, an
MPU-based ISSU upgrade applies and the service on this service card will not be interrupted. If Reboot
is displayed, a member switch-based or member switches-based ISSU upgrade applies and the service
on this service card will be interrupted for a short time.
Member switch-based ISSU upgrade for compatible and partially compatible versions
With this method, each member switch is considered as a separate switch.
To perform a member switch-based ISSU upgrade for a compatible or partially compatible version:
1. Upgrade a subordinate switch when the master is operating correctly.
2. Set the priority of the subordinate switch so that the subordinate switch has a higher priority than
the master.
3. Perform a master/subordinate switchover so that the subordinate switch becomes the new master.
4. Upgrade the former master and the other switches one by one.