GIS app loading very slow through F5 LTM

Right now there isn’t enough information to identify the cause. A 50-second delay alone isn’t enough to determine whether the issue is on F5, the network, or the backend application.

I would start by isolating where the delay occurs: DNS lookup, TCP/SSL handshake, F5 processing, or backend server response. On BIG-IP you can check the virtual server and pool member statistics, and run a tcpdump on both clientside and serverside. That usually shows quickly whether the delay happens before reaching the server or while waiting for the server response.

It’s also helpful to compare direct access to the server vs through F5, and check the browser developer tools waterfall to see which step is taking the time.

Hello,

you could use or adjust an irule like the one in 

Irule for getting total response time, server response time and server connection time | DevCentral

to log timimg during different events

Hi, 
Beside the below Comments, 

1- try to use Performance layer 4 for your GIS Virtual server , doing this ( BIGIP doesn't termintate SSL also doesn't perform HTTP pasrsing ). 

2- Take a PCAP and check the response time for this specific URI. 

3- Take HAR file from your browser to see this Latency from end user perspective. 

you can also bypass BIGIP from the path and access the application server directly for this URI, and check if the perfomance improved. 

All of the steps just to isolate, because this slowness maybe from the Application server. 

Also it's very important to ask the application developer/owner if this URI perform heavy DB Queries or not. 

Take also Pcap via standard Virtual server, and check if you encounter TCP error messages regarding Latencies like ( TCP Zero Window , Window Full ..... ) 

https://my.f5.com/manage/s/article/K35612380