Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 5 Configuring Virtual Switching Systems
In-Service Software Upgrade (ISSU) on a VSS
ISSU State = Init
Operating Mode = Stateful Switchover
Current Image = bootflash:y.bin
Pre-ISSU (Original) Image = N/A
Post-ISSU (Targeted) Image = N/A
Slot = 11
RP State = Standby
ISSU State = Init
Operating Mode = Stateful Switchover
Current Image = bootflash:y.bin
Pre-ISSU (Original) Image = N/A
Post-ISSU (Targeted) Image = N/A
Switch#
Configuring the Rollback Timer to Safeguard Against Upgrade Issues
Cisco IOS XE software maintains an ISSU rollback timer, to safeguard against an upgrade that may leave
the new active supervisor engine in a state in which communication with the standby supervisor engine
is severed.
You may want to configure the rollback timer to fewer than 45 minutes (the default) so that you need not
wait in case the new software is not committed or the connection to the switch was lost while it was in
runversion mode. Conversely, you may want to configure the rollback timer to more than 45 minutes in
order to have enough time to verify the operation of the new Cisco IOS XE software before committing
the new software image.
The ISSU rollback timer kicks in immediately after issu run version is entered so that the minimum
value configured should be more than the time required for a chassis reload. Else, the process fails.
Note The valid timer value range is from 0 to 7200 seconds (two hours). A value of 0 seconds disables the
rollback timer.
Once you are satisfied that the new image at the active supervisor engine has been successful and you
want to remain in the current state, you may indicate acceptance by issuing the
issu acceptversion
command, which stops the rollback timer.
Issuing the issu commitversion command at this stage is equal to entering both the issu acceptversion
and the issu commitversion commands. Use the issu commitversion command if you do not intend to
run in the current state for a period of time and are satisfied with the new software version.
Note
The rollback timer can be configured only in the ISSU Init state.
This task explains how to configure the rollback timer:
Command or Action Purpose
Step 1
Switch> enable
Enables privileged EXEC mode.
Enter your password if prompted.
Step 2
Switch# configure terminal
Enters global configuration mode.
Step 3
Switch(config)# issu set rollback-timer value
Configures the rollback timer value, which can range from
0 to 7200.