Data Transfer and File Size

Depending on the data size and number of files, we advise different possibilities for file transfer in/out of the RDMS.

Single files under 50 MB can be directly up-/ and downloaded via the RDMS web interface.

To download a file via the web interface, just right-click on the file in question, then select Download file from the context menu.

Note: If the Download file button is not visible from the context menu, the file size exceeds the limit of 50 MB. In this case, use one of the other options that we advise for data transfer (see below).

To upload a file directly inside the web interface, you first navigate to the destination folder. Afterwards, select the and select Upload File from the menu. You can upload a maximum of 10 files at once, as long as the total size of the selected files does not exceed 50 MB.

The data transfer of larger files is not possible via the RDMS web interface. There are various clients and command-line tools such as iCommands to transfer data to RDMS, add metadata, or perform more advanced tasks.

iCommands is a Unix utility that gives users a command-line interface. Currently, it is the most efficient way of transferring data, creating metadata, and performing more advanced tasks. In order to use the iCommands you need to work in a command-line tool such as a console, shell, or a terminal. For further information, please check the iCommands section of this manual.

WebDAV is a common file transfer protocol. For Windows, MacOS and Linux, there are multiple WebDAV clients you can use.

We currently recommend and provide support for:

• Windows: Cyberduck and WinSCP
• MacOS: Finder and Cyberduck
• For Linux: WebDAV on Linux

For large data (sets) in the order of several hundred GB or higher, the iRODS-native iCommands are the best solution.

Here are three different ways to use them:

• Via Hábrók cluster: The Hábrók HPC cluster has a fast network connection to the RDMS and the iCommands are already pre-installed on the cluster. It is therefore also possible to first transfer the data to Hábrók via SSH file transfer. Of course, you do need an account for Hábrók, but then you can upload to one of the storage locations that are available on the cluster. For intermediate storage on the cluster for transfer to the RDMS, we recommend that you use the /scratch directory on Hábrók.

• Via a Linux OS: See the manual on installing and using iCommands on Linux.
  If you do not have a Linux OS available, you can also use the Linux workplaces (LWP) provided by the university. Within the LWP, the iCommands are pre-installed. There also exists a virtual LWP version that can be accessed via the browser. For more details on the usage of the LWP, you can also refer to the LWP wiki.

• Under Windows: Microsoft offers the possibility to install the 'Windows Subsystem for Linux', or, in short, WSL2. This is a virtualization of the Linux kernel in the Windows OS. After successful installation of WSL2, you can install iCommands within the virtual Linux environment and use it for data transfer.
  Note: On university-managed Windows installations, so-called 'UWP', WSL cannot be installed and used.

Independent of the total size of the data, it is recommended that data sets that contain a large number of single files (thousands of files and more) are uploaded as an archive, for example as a zip or a tar archive. Uploading the files while in a zip/tar archive will tremendously reduce the operation time.