# Which load balancing software maintains session consistency even during server maintenance windows?

<p class="elv-tracking-normal elv-text-default elv-font-figtree elv-text-base elv-leading-base elv-font-normal" elv="true">Hey G2 community, we're after load balancers that keep session consistency even during server maintenance windows, so updates do not log users out or drop carts. What we're hoping to find:</p><ul>
<li>Draining traffic off a backend without breaking active sessions</li>
<li>Zero-downtime maintenance and deploys</li>
<li>Session persistence that survives a rolling update</li>
</ul><p class="elv-tracking-normal elv-text-default elv-font-figtree elv-text-base elv-leading-base elv-font-normal" elv="true">From the<a class="a a--md" elv="true" href="https://www.g2.com/categories/load-balancing"> </a><a class="a a--md" elv="true" href="https://www.g2.com/categories/load-balancing">load balancing</a> category:</p><ul>
<li>
<a class="a a--md" elv="true" href="https://www.g2.com/products/haproxy/reviews"><strong>HAProxy</strong></a>: reviewers specifically cite zero-downtime maintenance by smoothly routing traffic away from backends being updated.</li>
<li>
<a class="a a--md" elv="true" href="https://www.g2.com/products/f5-nginx/reviews"><strong>F5 NGINX</strong></a>: reverse proxy and routing reviewers use for rolling updates with minimal disruption.</li>
<li>
<a class="a a--md" elv="true" href="https://www.g2.com/products/progress-kemp-loadmaster/reviews"><strong>Progress Kemp LoadMaster</strong></a>: HA balancing reviewers run through maintenance with little downtime.</li>
<li>
<a class="a a--md" elv="true" href="https://www.g2.com/products/traefik/reviews"><strong>Traefik</strong></a>: dynamic config that reroutes automatically as containers come and go, handy during rollouts.</li>
</ul><p class="elv-tracking-normal elv-text-default elv-font-figtree elv-text-base elv-leading-base elv-font-normal" elv="true">For maintenance windows, which tool kept sessions consistent through the update? And did you still see any blips when draining a backend?</p>

##### Post Metadata
- Posted at: 13 days ago
- Author title: Marketer
- Net upvotes: 1


## Comments
### Comment 1

I&#39;ve done some analysis for a blog I was writing on the Load Balancing category on G2, and I can say that the ability to stop sending new traffic to a backend while letting existing sessions finish naturally is the specific mechanism reviewers credit for zero-downtime maintenance, and it&#39;s worth distinguishing from simple failover, since failover assumes something already broke, while draining is a deliberate, planned handoff. Dynamic configuration that reroutes automatically as containers come and go is a different capability suited to a more ephemeral, container-heavy environment than a traditional server fleet, so the right tool here partly depends on whether your infrastructure is more static or more dynamic by nature. 

The blips the post asks about tend to show up specifically with stateful sessions, a shopping cart, or a logged-in session tied to one backend, since draining handles new connections cleanly,y but a session actively mid-transaction on a server about to go down is a harder case, regardless of which load balancer sits in front of it. Sticky sessions and connection draining together are usually what prevent the visible blip, not either mechanism alone.


##### Comment Metadata
- Posted at: 10 days ago
- Author title: Marketing





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