Efsu stages for a vss upgrade – Cisco 6500 User Manual
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Cisco IOS Software Configuration Guide, Release 12.2SX
OL-13013-06
Chapter 4 Configuring Virtual Switching Systems
Upgrading a VSS
eFSU Stages for a VSS Upgrade
The eFSU sequence consists of several stages, each explicitly initiated by entering a specific issu
command in the CLI. At each stage, you can verify the system status or roll back the upgrade before
moving to the next stage.
The following sections describe the eFSU stages for a VSS upgrade:
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Acceptversion Stage (Optional), page 4-57
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Commitversion Stage, page 4-58
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Abortversion (Optional), page 4-58
Preparation
Before you can initiate the eFSU process, the upgrade image must reside in the file system of the
supervisor engine in each chassis; otherwise, the initial command will be rejected. The VSS must be in
a stable operating state with one chassis in the VSS active state and the other chassis in the hot VSS
standby state.
Loadversion Stage
The eFSU process begins when you enter the issu loadversion command specifying the location in
memory of the new upgrade images on the VSS active and VSS standby chassis. Although the issu
loadversion command allows you to specify the switch and slot number of the VSS active and VSS
standby chassis, it is not necessary to do so. When you enter the issu loadversion command, the entire
VSS standby chassis, including the supervisor engine and modules, is reloaded with the new upgrade
image. Because the VSS standby chassis modules are unavailable while reloading, the throughput of the
VSS is temporarily reduced by 50 percent during this stage. After reloading, the VSS standby chassis
boots with the new image and initializes in SSO mode, restoring traffic throughput. In this state, the VSS
standby chassis runs a different software version than the VSS active chassis, which requires the VSS
active chassis to communicate with modules running different image versions between the two chassis.
Runversion Stage
When the VSS standby chassis is successfully running the new image in SSO mode, you can enter the
issu runversion command. This command forces a switchover in which the upgraded VSS standby
chassis takes over as the new VSS active chassis. The formerly VSS active chassis reloads and initializes
as the new VSS standby chassis in SSO mode, running the old image. As in the loadversion stage, the
throughput of the VSS is temporarily reduced during the VSS standby chassis reload, and the VSS
standby chassis runs a different software version than the VSS active chassis.
Acceptversion Stage (Optional)
When you enter the issu runversion command, a switchover to the chassis running the new image
occurs, which starts an automatic rollback timer as a safeguard to ensure that the upgrade process does
not cause the VSS to be nonoperational. Before the rollback timer expires, you must either accept or
commit the new software image. If the timer expires, the upgraded chassis reloads and reverts to the