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rld_178240's avatar
rld_178240
Icon for Altostratus rankAltostratus
Nov 25, 2014

Slow application performance when using BIG-IP LTM VE for load balancing.

The Question   Is there some limitation on the BIG-IP F5 LTM that prevents it from being able to support a large user load and/or are there any configurations that could specifically interfere wit...
application delivery
LTM
management
performance
  • rld_178240's avatar
    rld_178240
    Feb 19, 2016

    The overall answer to this question is, yes there is a limitation... but it depends on the license type purchased. The license I had available to me had a 10 Mbps limitation on it, rendering it useless for load testing scenarios. This information in the assorted comment threads.

     

    The following references on F5 were helpful, but ultimately, I would have liked to find a SOL that explicitly calls out this limitation, as it feels somewhat masked (it may not be, when talking to account teams from F5, but unfortunately I came into this post-purchase.) It is not listed in the licensing information when running tmsh show /sys license.

     

    Thank you again to WLB for all of the help. It was WLB's guidance that helped me find the answer to this question. I am just posting the direct answer so that the thread can be closed.

     

What_Lies_Bene1's avatar
What_Lies_Bene1
Icon for Cirrostratus rankCirrostratus
Nov 26, 2014

Alright. Sorry for the delay. Interestingly enough I can across a similar issue in my own environment today where file transfers takes approx. 10x long via 'traffic' interfaces compared to the management interface.

 

We can probably leave the TSO/LSO options alone, especially if FastL4 isn't being used. SRV-IO would be nice but shouldn't make a massive difference.

 

  • Create custom client and server side TCP profiles

     

  • I'd suggest bumping the TCP initial congestion window up to 10 if you can - server and client side, this should be done on the servers/hosts: http://andydavies.me/blog/2011/11/21/increasing-the-tcp-initial-congestion-window-on-windows-2008-server-r2/ and within the TCP profile changing the Initial Congestion Window Size from the default of 0 (which actually means 4).

     

  • Enable Proxy MSS client side

     

  • Up the Initial Receive Window Size server side

     

  • If client side is lossy/wireless, consider enabling D-SACK*

     

  • Ensure Congestion Control is set to High Speed. If clients are on a lossy network, consider New Reno instead.

     

Let me know how you get on.