File upload on 31.2.1 is very slow for large files.

Products

• VMware Avi Load Balancer

Issue/Introduction

Users may experience significantly slower upload speeds for large files when using version 31.2.1 compared to the 30.2.x release cycle. This performance hit occurs during HTTP/HTTPS requests regardless of whether specific traffic processing features are enabled.

Environment

All Environments

Cause

The performance bottleneck was traced to a logic change introduced in the content rewrite engine of version 31.2.1.

In this specific version, the system was erroneously building a linked list for every request chunk processed. This overhead was being applied universally, even in scenarios where it was unnecessary, such as:

• Streaming Mode: Where data should pass through without being buffered.

• Disabled Content Rewrite: Where no modifications to the payload are required.

The constant allocation and management of these linked lists created a cumulative delay that became particularly noticeable during high-volume data transfers (large file uploads).

Resolution

This issue has been resolved. The fix ensures that linked list construction is bypassed when content rewriting is disabled or when the system is operating in streaming mode.

There is not workaround available for the issue. The fix is available in 31.2.2-2p1 release

Bug ID: AV-268368

Release Notes: 31.2.2-2p1