im wondering about migrate from on-premise TFS 2018.2 to on-premise DevOps Server but cant find any tool for migrating tfs collection to on-premise server.
Did any one of you have any suggestion?
DevOps Server 2019 is just a rename for TFS.
First make sure you backup your VM (if a VM) or/and the TFS databases.
You can just uninstall TFS 2018.2 (leave the database there) then install Azure DevOps server 2019 and select the upgrade path and it will upgrade in-place.
you have some information here: https://learn.microsoft.com/en-us/azure/devops/server/upgrade/get-started?view=azure-devops and here: https://learn.microsoft.com/en-us/azure/devops/server/upgrade/walkthrough?view=azure-devops
Good luck