June 20, 2016 at 9:24 am
Hello!
I've just finished to migrate all my production DB to a new SQL 2014 Box, built on an Hyper-v Guest.
All is working well but we have found some issues related to the network
The ERP Application make some queries to the DB to display a few reports, but since we are on the new server, some of them are really slow.
I can compare the elapsed times directly to the old server and the differences are huge.
Looking with some DMV I get that the wait that arise on the new server is ASYNC_NETWORK_IO. I know that usually this wait is due to the client, but the same client, if it points to different servers, havetotally different timings.
The single query on the server is processed really fast (even on the old server) and the returned rows are the same. I've looked at the network configuration of the guest OS and the Host OS and nothing appears to be or under pressure.
Does anybody have a clue to explain me this heppening?
Thank you!
June 21, 2016 at 5:38 am
Interesting problem, if everything seems fine in the Guest OS of a VM my next course of action is to go and talk to the admins who have access to the hyper-visor monitoring tools to see what is going on with the host and how its network is configured.
Somewhere along the line I suspect there are some network settings that need adjusting, the network 'health' as far as the two servers go would look fine - the SQL Server is sending the packets as fast as it can, and the app server is receiving them as fast as it can.
Are there any other SQL Servers on the same host? If so can you test using them to see if the same problem exists?
June 30, 2016 at 2:33 am
UPDATE
I found that windows 2012 starts up with the balanced power saving mode....
Changed this both on VM and Host machine and performance pumped up a lot, but still not equal to the previuos environment.
Still searching...
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