Forum Discussion
CR_266055
Nimbostratus
NimbostratusSlow File upload and download Speeds via F5 BigIP
We have encountered a lowness issue for file upload/download. We tested our application in the IIS web server and it is super fast. Once we go through F5, it becomes extremely slow. Can anyone sha...
Yann_Desmarest
Cirrus
CirrusHi,
Can you check if tcp profile attached to the virtual server don't use nagle algorithm ?
There is also bufferand timeout settings you can play with at the tcp and http level.
Do you have an asm security policy activated on your VS ?
I recommend to run a fiddler on the client side to verify where is the pain
CR_266055we did fiddler and cannot see anything obvious. I found an article 2009 on this site that is similar but no specific configuration mentioned just saying F5 is the issue.- Yann_Desmarestok for fiddler, what about my other questions
- CR_266055IT made the changes suggested in the 2009 article which also suggesting to turn off nagle algorithm, same issue.
- Yann_DesmarestIs it an upload through http or https ? You may have packet fragmentation and retransmission of tcp segments before or after the packet enter or leave the bigip. You can execute a tcpdump command on the bigip and then analyze results with wireshark
- Yann_DesmarestSometimes I got probes or tap devices that slow down the flow cause of the mtu
- CR_266055Download via https. is it possible that https is the issue?
- Yann_DesmarestYes, it can be an issue and for many reasons.
- Yann_Desmarestwhen using SSL, the MTU of each packet increase and sometimes force some network devices to fragment or drop some packets forcing retransmission and congestion control activation
