I'm hoping this is the correct section for this post. I'm running into a little bit of a snag on high log send queue in a 2014 SP1 Asynchronous Mode AlwaysOn Environment with a secondary replica in Azure. For one of our higher transaction volume DB, we are seeing log send queue sizes up to nearly 2GB. Initially we saw a CPU bottleneck on the secondary due to the sizing of the Azure VM, which we corrected. However we were still left with some high log queue sizes and slow send rates, coupled with respective high re-dos.
We traced this back to an issue with IO using the follow error log message:
There have been 112313856 misaligned log IOs which required falling back to synchronous IO. The current IO is on file...
This knowledge base article seems to address exactly what my issue is:
However its a year old and it last applies to CU5, which is about a year old, and we are about 8 patches past CU5. Additionally I cant find any official documentation from MS on trace flag 1800. Does anybody have an similar experiece with either this issue or traceflag 1800?