Forum Discussion
rld_178240
Altostratus
AltostratusSlow 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...
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.
- https://devcentral.f5.com/questions/limited-bandwidth-on-virtual-edition
- https://devcentral.f5.com/questions/f5-big-ve-lab-license
- https://devcentral.f5.com/questions/bigip-ltm-ve-lab-limitations
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
Cirrostratus
CirrostratusOK, standard set of questions here;
- Please double-check all vNICs (apart from mgmt) are VMXNET3
- What TCP profile settings are being used client and server side?
- What vNICs are assigned to the servers?
- Are you using any FastL4 virtuals?
- Have you enabled TCP Segmentation Offload (TSO) in VE?
- Have you enabled Large Receive Offload (LRO) in the hypervisor?
- If your physical host NICs support it, have you enabled SR-IOV support?
There's lots of factors that may influence things and that can be tweaked including;
- TCP Slow Start
- Nagle (disabled by default) and Delayed ACKs (enabled by default)
- Server/host receive window, initial congestion window etc.
Anyway, if you can answer/investigate my initial questions we can take it from there.