Bug ID 466266: In rare cases, an upgrade (or a restart) can result in an Active/Active state

Last Modified: Oct 06, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP Install/Upgrade, LTM(all modules)

Known Affected Versions:
11.2.1, 11.4.1, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4

Fixed In:
12.0.0, 11.6.0 HF5, 11.5.3

Opened: Jun 09, 2014
Severity: 2-Critical
Related AskF5 Article:


After upgrading or restarting, the system starts up in an active state even if the peer system is already active.


The impact of this issue is that both systems take traffic.


An upgrade or system restart for an active/standby pair. The issue occurs intermittently and is timing-dependent. There is code executed during sod's initialization that attempts to detect when communication between mcpd and sod has gone bad; this code does this by checking for "end transaction" messages. If 30 or more messages from mcpd are received without an "end transaction" message, sod will reset its connection with mcpd. While the connection is being reset, it is possible for sod to miss messages from mcpd. Depending on which messages it misses, sod may end up in a bad state and exhibit the symptoms of this bug. If this occurs after an upgrade, it does not matter which version one is upgrading from.


Restarting the 'sod' daemon on the system after an upgrade or reboot clears the condition. This causes the system to go offline and will disrupt traffic. Standard BIG-IP appliance: bigstart restart sod VIPRION system: clsh bigstart restart sod

Fix Information

In this release, the system ensures that an upgrade or a restart can never result in an Active/Active state.

Behavior Change