Forum Discussion
swo0sh_gt_13163
Jun 24, 2015Altostratus
Hello Folks,
Sorry I couldn't update the thread. I have actually escalated to F5 Support, and run of the case was almost 3 months, and it was escalated to PD etc, and finally it end up with the bug, with existing firmware version.
Following was resultant update from Support.
PD has found the problem.
They confirmed that it's indeed caused by OneConnect and we have a potential fix under review.
Disabling OneConnect or switching to round-robin are effective workarounds.
The customer can also upgrade to 11.5.0+ where this is no longer an issue.
Hotfix-BIGIP-11.2.1-HF13-1306.15-ENG.iso has been uploaded to the dropbox, it contains the fix for **BZ504538**.
I tested it in the lab, and LC+OneConnect is working as expected.
So basically, OneConnect and LC cannot work well together, following are low level technical details for the same.
In regards to oneconnect+least-connections:
1. The customer's issue is that they have uneven distribution of load balancing. This is exactly what sol2055 describes.
2. Least-connections and oneconnect is a problematic combination because least-connections is trying look at currently used, open TCP sockets to the backend server. Oneconnect is trying to minimize the open TCP sockets to the backend servers by re-using the sockets for multiple HTTP requests.
3. [https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm-concepts-11-2-1/ltm_pools.html?sr=42995518](https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm-concepts-11-2-1/ltm_pools.html?sr=42995518)
The Docs on least-connections say:
"Note: If the OneConnect feature is enabled, the Least Connections methods do not include idle connections in the calculations when selecting a pool member or node. The Least Connections methods use only active connections in their calculations."
That means that the idle tcp sockets being held open by one connect are not part of the least-connections calculation. This is one reason for the discrepancy mentioned by sol2055. Idle oneconnect connections will remain open and count as an open connections depending on which stats you look at ( and certainly these are open connections according to the web servers) but these connections will not be used by tmm for a least-connections calculation.
4. While looking at their connection table, the number of non-idle concurrent connections in their environment is not sufficient for least connections to even begin working properly. Analyzing their connection table shows *one* connection open:
Based on the above, I would suggest the customer utilize round robin instead of least-connections, especially if they want to keep using OneConnect.
I hope this would be useful. Apologies to take such a long time to update the thread.
Cheers! Darshan