Skip to main content

Team Foundation Server: Be careful when using the ChangeServerId command

Before I upgrade a production TFS environment, I always try do to a test migration. This gives us the opportunity to detect possible issues as soon as possible and give some people the change to test the new environment before we do the real migration.

What you need to be aware of when doing this is that TFS uses a set of internal GUIDs.  The server has a GUID, the collections have GUIDs and even Team Projects have GUIDs.This means that when you do a migration your new TFS environment will use the same GUIDs out-of-the-box. This is nice because when a user connects to another server with the same GUIDs Visual Studio will automatically transfer all of the user’s cache and workspaces to the new server. This makes an upgrade really convenient and transparent for the user.

So this is perfect for the ‘real’ migration, but for the ‘test’ migration it’s a problem. Because the moment any user tries to connect to the new environment, he gets into trouble when trying to connect to the old environment again(causing some really strange behavior).

To solve this problem you can use the ChangeServerID command:

TFSConfig ChangeServerID /SQLInstance:ServerName] /DatabaseName:ConfigurationDatabaseName [/ProjectCollectionsOnly] [/ConfigDBOnly] [/usesqlalwayson]

However it’s very important that you run this command BEFORE configuring your application tier. If you run it afterwards, you get the following warning:

The command ChangeServerId should only be run against a set of Team Foundation Server databases that have no application tiers configured. Do you want to continue with this operation? (Yes/No)

If you type Yes the command will still be executed but TFS is no longer available. So please really read your warnings Glimlach

In case this happens to you, the following command will bring rescue:

TFSConfig RegisterDB /SQLInstance:ServerName [/usesqlalwayson]

More information about this issue can be found here: http://nakedalm.com/guide-to-changeserverid-says-mostly-harmless/

Labels:

Popular posts from this blog

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME         ...
Read more

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...
Read more

A complex system designed from scratch never works

A few years ago, I worked as an architect on a big mainframe rewrite. I still count it as one of my failures. Not because the technology was wrong, but because I couldn't convince the management team to simplify the approach. Years later, the organization is still struggling to get the new system up and running. I left the project at the time, because I couldn't put my name behind an approach that would take very long and cost a lot of money without a working system to show for it along the way. Gall’s Law That memory keeps coming back to me, because it's a textbook case of Gall's Law playing out in real life. Gall's Law , from John Gall's Systemantics , states it plainly: A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works, and it cannot be patched to make it work. You have to start over with a simple system that works. What does that mean in practice,...
Read more