Due to technical limitations we are not able to proactively restrict a user session to a set of resources on a dialog system. This means that every user can make use of all resources of a dialog server and potentially exhaust it or cause it to crash in certain circumstances. Please bear in mind that your computations on the dialog system can have direct effect in the user experience of other users on the system. The dialog systems are intended for testing, pre- and post processing of HPC batchjobs and not meant for running big computations.

Nevertheless, to keep resources available and limit the risk of freezing or crashing servers we've implemented some limitations and give some guidelines which are explained below.

1. Process kills due to memory exhaustion

If the available memory on a dialog system is low the response times of all sessions on the affected server will drop significantly. In certain cases even system services will stop responding and the system might crash, resulting in potential data loss for you and all other sessions on the affected system. If your process consumes too much memory on a dialog system, these processes will be killed and you will be notified by a popup window.

2. Core limitation of long running processes

If the CPU Time on a dialog system is low, the response times of all sessions on the affected server will drop and users will experience extreme lags in interactions with their session. To avoid that, processes which consumed more than 20 Minutes of CPU Time will be bound to a subset of available cores in order to keep the system responding. There might be false positives like long running browser sessions. In these cases just restart your browser/application.

3. Disconnect of idle sessions

If your session is idle for 24h, your session will be disconnected to free these resources for active users.

4. Local Disk space

  • User Profile size: User profiles are files stored in C:\Users\<username> and are copied from your Homefolder to this location at login time and copied back at logoff. The size of the profile is limited to 2GB. If your profile exceeds this size, you will be notified by a popup window, telling you to reduce it. If you do not follow this request, your profile cannot be copied back on logoff and you might lose new data stored in it. Typical folders which can grow very large are e.g. c:\user\<username>\.cfx, the Thunderbird offline cache or a dropbx cache. These applications per default save data in your profile instead of your Homedrive. Be sure to configure them to store data on H:\!

  • C:\ : Some users try to store data or applications on C:\. Do not create files or folders on C:\, because they will be deleted automatically and without warning!

  • %TEMP% or D:\TEMP\<username>: Most applications need a location to store temporary data, most of them use %TEMP% for this purpose. For this requirement, we provide a directory on D:\temp\<username>. Again, there is very limited disc space. Please try to configure your application to use working directories on W:\ where applicable and possible. Data in %TEMP% will be deleted at session logoff.