Frequently Asked Questions

  1. General
    1. Is my data safe?
    2. Who can view my data?
    3. I am suddenly getting only "Permission Denied"!
  2. PostgreSQL
    1. Which are my PostgreSQL userdata?
    2. psql warning: old client
    3. Why is the PostgreSQL database name this complex?
  3. MySQL
    1. Which are my MySQL userdata?
  4. Repositories (General)
    1. I cannot access my SVN repository! (General)
    2. I cannot access my SVN repository! (Forbidden)
    3. Soft-Quota
    4. Association of Repository and Project Management Environment
  5. Git
    1. Strange things are happening while using Git!
    2. Save Credentials
  6. Subversion
    1. Trac
      1. Why is Trac-plugin installation forbidden?
      2. Authentication of external users possible?
    2. Tomcat
      1. Deployment fails
    3. Redmine
      1. Logout on Setting a Parent Ticket for a Ticket


    Is my data safe?


    I don't want to loose my project's data. How likely is that case?


    We are no high-security computer center, but in the past it worked well.

    Who can view my data?


    My project data is off the record. May I use the projects-server for this project?


    For data that's stored on the server (e.g. databases, repositories) the administrator is the only one who could see your data. I'll be damed if I will look into your data.

    However, if your project is super-secret and you're working for a company for which you signed an NDA, you should think about an own server, e.g. one of the FB4. Forms are available in the 6th floor of building C.

    I am suddenly getting only "Permission Denied"!


    If I want to access one of my projects (GIT, HG, SVN, Redmine, Trac, Tomcat), I only get an Permission Denied. Yesterday, it worked fine!


    If there has been the 1st April or 1st October between the last usage and now, your project has been deactivated for sorting out unused projects.

    We do this because we want to sort out inactive projects. Your data is safe for one or more semesters, depending on the service (more details in the overview of the service).

    You can reactivate the project at any time by pressing the button its detail screen.

    If none of the mentioned-above days apply, please check if it is deactivated, anyway. If not, the FAQ entries below may provide more info.


    Which are my PostgreSQL userdata?


    I cannot connect on the PostgreSQL database! Which is my username and password?


    Username and password are identical to the FB4 account you use to login to this site.

    psql warning: old client


    My psql-client (e.g. on charon) shows the following warning on login: WARNING: You are connected to a server with major version 9.0, but your psql client is major version 8.3. Some backslash commands, such as d, might not work properly.


    As far as I know the warning is right. All normal SQL-Queries should work properly. However, if you finde one that does not work, please contact

    Why is the PostgreSQL database name this complex?


    The PostgreSQL database names are very complex. Are those underscores really neccessary?


    Yes, they are. On one hand side, the first character of the database name must be valid - thats the first underscore. On the other side, students are technically spoken not the owner of their databases, for administrator's sake. That's why the webserver must determine the owner of a database efficiently from the database's name - and thats everything before the double underscores.


    Which are my MySQL userdata?


    I cannot connect on the MySQL database! Which is my username and password?


    On first access to a page related to the MySQL service you are asked to enter a password. You can change it later via the corresponding link in the sidebar of every MySQL page. The username is the name you are logged in with on this site.

    Repositories (General)

    I cannot access my SVN repository! (General)


    I cannot access my repository! My client is reporting strange errors such as redirects.


    It is likely that you are using the wrong URL. Notice that you must not use the web interface URL ([svn|git|hg]/detail/[name]), but the right one which has the pattern[svn|git|hg]/[Benutzername]/[Reponame]/!

    This URL is shown in the details of every repository and immediatly after its creation.

    I cannot access my SVN repository! (Forbidden)


    I always get a "forbidden" response on accessing my repository. Is my repository faulty?


    No. This can have two reasons:

    1. Your URL is faulty
    2. The repository is not included in the server configuration

    In the first case please check if even the hotlink in the details of your repository doesn't lead you to a valid path. It's an URL like[svn|git|hg]/[username]/[reponame]/.

    In the latter case the repository may be marked as inactive, so you can easily re-activate it in its details, or, unlikely, the server configuration is not up to date. In this case you can trigger a refresh by removing and re-adding a random user from this repository.



    What does Soft-Quota on repositories mean?


    Repositories do not have a hard quota (limit of disk size) at our server because we do not want to constrain you while studying. But there is a limit at which it is likely that you are using your repository wrong.

    That is why you get a warning mail if your repository exceeds a certain soft quota, explaining the correct usage of a repository again, which you can also find in the corresponding tutorial (coming soon). Also, you get warned that administrators may analyze your repository if you exceed another certain limit.

    If you have a big project you can mail us and describe why you need so much space to be excluded from this mechanism.

    Association of Repository and Project Management Environment


    What exactly does the connection between a repository and a project management environment mean?


    This only means the repository in question is registered in the project management environment's settings. In the case of Redmine and Trac this enables you to use features like the code browser or view repository events in the history.

    This does not mean that authorized users of a repository have automatically access to the project management environment or vice versa! The projects server should offer maximum flexibility, so it only applies the settings mentioned above.

    Why don't we let you do these settings on your own? The reason is simple: The access to the repository is done via the file system, so if you could enter every path in Trac, you could browse every repository on the server without access control.

    Please note this connection is neither revertable nor could it be established after creation.


    Strange things are happening while using Git!


    "git clone" raises strange permission errors, or "git push" fails with similar problems. What's happening?


    Git via HTTP(S) has been a pain, especially with read-protection. This is why our server uses the modern smart HTTP (git-http-backend). A client based on Git 1.6.6 or more is required. Everything other belongs into a museum!

    Save Credentials


    I'm used to clients that save my credentials, like SVN clients do. Git doesn't, that's getting on my nerves!


    Git uses CURL for executing HTTP(S) requests, which in turn can store credentials for servers in a special file:

    login [Username/Matrikelnummer]
    password [Password]


    Create the file .netrc in your home directory and paste the data.


    On Windows, you must first create the HOME environment variable:

    1. System (Windows-Key + Pause-Key)
    2. Advanced Settings
    3. Environment Variables...
    4. User variables new...
    5. Enter an arbitrarily path

    Under this arbitrarily path, create a file called _netrc and paste the data.



    Why is Trac-plugin installation forbidden?


    I want to install a per project Trac plugin in the TracAdmin, but I can't find the corresponding menu item!


    Sorry, installing per-project plugins is forbidden. The main reason is we can't control which plugins students will install. There are plugins available for controlling the Trac settings from the Browser, so you could simply access a repository of someone else or do things the admin couln't even imagine of.

    If you need a plugin for a project, open a ticket and it will get installed as soon as possible if it is secure. If it's cool in addition, it may get installed for all environments!

    Authentication of external users possible?


    A person involved into a project has no FB4 account. How can I grant him access to my Trac instance?


    If the person is member of the HTW, please ask her to aquire an FB4 account!

    It is a rarely requested feature to let non HTW members participate on a project. That's why this function is not implemented (yet). Single Trac accounts can be created via the support (Ticket, Mail).


    Deployment fails


    On deploying a WAR archive the server tells me it cannot be deployed and it may be corrupted. But it works perfectly on my home computer!


    This may have one cause: You compiled the WAR archive with libraries of a different Tomcat version than installed on our server.

    Please note we are running Tomcat 6, not Tomcat 7, thus archives compiled with the latter will fail to deploy. The current running version is shown on the Tomcat page where you deploy your webapps.


    Logout on Setting a Parent Ticket for a Ticket


    If I want to add a parent ticket for a ticket after I created it, I'm logged out and the changes are lost. Why is this?


    This seems to be a Redmine bug. A possible workaround: Activate the "always logged on" checkbox while logging in. In addition, it is no problem to set a parent ticket while creating a new ticket. Just use the add button in the children tasks area of the parent ticket.