Forum Discussion
bigip001_4000
Nimbostratus
Nimbostratusfasthttp - maximum pool size
What is meant specifically by the following fasthttp option:
https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm_configuration_guide_10_1/ltm_protocol_profiles.html1187505
-Maximum Pool Size
Specifies the maximum number of connections a load balancing pool can accept. A setting of 0 specifies that there is no maximum; that is, a pool can accept an unlimited number of connections.
Default - 2048
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Is this referring to the total amount of connections coming in on all the pool members or the pooling of server side connections? The default is 2048, does that mean the total amount of connections a given pool can take in is 2048 with fasthttp enabled unless this option is changed from the default?
hoolioCirrostratus
Hi,
Those properties of the FastHTTP profile refer to the OneConnect settings for the profile. So my interpretation of the max pool size count is that it indicates how many idle serverside TCP connections LTM will maintain at any given time. This is based on the details in SOL7208:
SOL7208: Overview of the OneConnect profile
https://support.f5.com/kb/en-us/solutions/public/7000/200/sol7208.html
OneConnect Profile Settings
...
The Maximum Size setting represents the maximum number of idle server-side connections kept in the connection pool.
The Maximum Age setting represents the maximum number of seconds a server-side connection is allowed before the connection is deleted from the connection pool.
I imagine that LTM would open more than 2048 server side connections if that were necessary to handle the client side requests. I don't think LTM would queue or close the clientside requests and keep only 2048 connections open between itself and the pool members if the serverside connection pool was "full". Maybe someone here can correct or confirm these assumptions.
You could also test this by setting the limit to 1 or 2 and making a few requests to the VIP with a tcpdump running.
If you'd like confirmation from F5 and/or for them to update the LTM config guide to make this more clear, you could open a case with F5 Support.
Aaron
bigip001_4000Aaron,
This pointed me in the right direction and I think I fully understand now, thank you very much for the response.