TechTips - Unknown SQL Exception 53 Occurred, Cannot Connect to Configuration Database

I am finding more and more errors come from my MOSS 2007 SharePoint Farm than any other server I have on my network. Most recently this error came up and took down my entire 2005 SQL server.

Unknown SQL Exception 53 occurred.

Event Type: Error
Event Source: Windows SharePoint Services 3
Event Category: Database
Event ID: 5586
Date: 5/6/2010
Time: 4:15:00 AM
User: N/A

Unknown SQL Exception 53 occurred. Additional error information from SQL Server is included below.

A network related or instance specific error occurred while establishing a connection to SQL server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL server is configured to allow remote connections. (Provider: Named Pipes Provider, error 40 - Could not open a connection to SQL server)

I looked all over for a solution and found many suggestions but none of them worked for me. First I want to point out that I was able to Ping my SQL server and every server in the SharePoint Farm. I was able to remote to each of them and there didn't seem to be any network issues. So I went to work on finding my own solution and tried the following things.

1 - Restarted my SQL services on the SQL server - didn't solve the problem

2 - Restarted IIS on my web servers (iisreset) - didn't work

3 - Rebooted all my web servers in my SharePoint Farm - didn't help

4 - Click Run, type Cliconfg, added named pipes and TCP/IP and checked the enable shared memory box - didn't help (I changed these settings back)

5 - Rebooted my SQL server - didn't help

6 - Reset my SharePoint passwords (guide here) - didn't help

7 - Checked to be sure my service account was not locked out, expired, or password expired - it was ok

None of the above worked so finally just a random thought that I came up with that ended up fixing my problem. I went to my NIC card and added in the QoS packet scheduler service. Once I put this into the NIC card everything started to work again. The QoS packet scheduler service provides network traffic control and prioritizes services, so I am assuming it helped to sort out all the requests coming in and out of my SQL box.

So the next step is how to install the QoS Packet Scheduler service?

Pretty simple actually (warning it will disconnect your remote session if you are on the server via remote desktop) just follow the steps below:

1 - Click on Start

2 - Click on Control Panel

3 - Double Click Network Connections

4 - Right Click on your active network connection

5 - Choose Properties

6 - Click on the Install button

7 - Click Service

8 - Click Add

9 - In the left hand pane click Microsoft (as manufacturer)

10 - In the right hand pane click QoS Packet Scheduler

11 - Click OK (this is where you will get disconnected, but you can reconnect right away)

12 - You can do the first 5 steps to be sure the service was installed, it will show up in the network connections properties and should be checked, which means it is enabled.

Check your websites\SharePoint sites and see if you can now connect to the SQL server. This solved my problem, you may have to reboot your servers before this setting works, I didn't have to but just keep in mind to try that if it doesn't work right away.

Well I hope this helps you to solve your problem.