Bug ID 515072: Virtual servers with priority groups reset incoming connections when a non-zero connection limit is increased

Last Modified: Oct 01, 2018

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
11.0.0, 11.1.0, 11.2.0, 11.2.1, 11.3.0, 11.4.0, 11.4.1, 11.5.0, 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, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5

Fixed In:
12.0.0, 11.6.0 HF6, 11.5.4, 11.4.1 HF9

Opened: Mar 29, 2015
Severity: 3-Major
Related AskF5 Article:
K17101

Symptoms

When a virtual server has priority groups and connection limit configured, if the connection limit is reached and is increased while the member is limited, then subsequent connections will be reset rather than allowed.

Impact

New connections are reset without being able to send traffic.

Conditions

Using priority groups and a non-zero connection limit, with one of the following load balancing methods: least-connections-member, least-sessions, ratio-member, ratio-least-connections-member, ratio-session. The issue occurs when the connection limit is adjusted higher when the connection limit is reached on the high-priority pool.

Workaround

If it is feasible to adjust the priorities, adjust the connection limit to its initial value, and adjust the priority groups so that the traffic currently on the limited pool drains out. When the pool has no connections, increase the limit to restore the correct priorities.

Fix Information

Make pool member eligible for load balancing if its not connection limited after modifying its connection limit.

Behavior Change