Data Management

This section gives you information about PDC’s storage solutions. Working with PDC can involve transferring data back and forth between your local machine and PDC resources, or between different systems at PDC.

If you have NAISS Swestore allocation, please check File transfer section on how to transfer files to/from Swestore.

Where to store my data

As the speed of CPU computations keep increasing, the relatively slow rate of input/output (I/O) or data accessing operations can create bottlenecks and cause programs to slow down significantly. Therefore it is very important to pay attention to how your programs are doing I/O and accessing data as that can have a huge impact on the run time of your jobs. Here, you will find a quick guide to storing data, ideal if you have just started to use PDC resources.


Klemming is the center storage system at PDC. It uses the Lustre parallel file system, which is optimized for handling data from many clients at the same time. The total size of Klemming is 12 PB (12,000 TB).


Swestore is a large scale storage system for live research data provided by NAISS. It requires a separate allocation to use. Part of the Swestore system is hosted at PDC.

File transfer

We recommend the following methods for transferring files to and from PDC:

  1. scp/rsync: With Secure Copy (SCP) and rsync you can copy files between your local machine and PDC systems. They use SSH for data transfer, and thus the same authentication as for logging in.

  2. Swestore (dCache): If you have NAISS Swestore (dCache) allocation, please see here how you can transfer files to/from it.

  3. KTH OneDrive (rclone): Use to transfer data between PDC and KTH OneDrive cloud storage.

Nodes for file operations

At PDC we have a number of transfer nodes setup. These nodes are dedicated for large file transfers but also for extensive file operations involving large amount of data or many files. It is important that you use these nodes for extensive file operations as not to overload the login node.

Dedicated transfer nodes for large file transfers will be set up on Dardel. In the meanwhile, please use the login node for the file transfers.




Login node (Dardel)

Submitting jobs and small file transfers

Login node (Dardel)

Large transfers and operations on the file system

PDC environmental variables

To simplify for the user how to find different folders, PDC has provided a number of specific variables which indicate in which folders data should be stored. These variables are loaded by default

Table of the environmental variables



Location on Dardel


Where important data are backed up.

Your klemming home directory


Name of the cluster you are logged into



Name of the site



Scratch folder for storing temporary data



Singularity containers folder