Data Transfer Options on SuperMUC-NG


SuperMUC-NG provides a high performance network connection to the outside world. In order to perform easy and fast data staging to/from SuperMUC-NG, we provide various data transfer methods. However, because of limited support resources, there is a distinction on what is available to transfer data to/from arbitrary external sites and to/from our GCS and PRACE partner sites. In the following document, we want to give you the necessary information on using the available data transfer options.

SuperMUC-NG DTN Setup

The diagram below shows the SuperMUC-NG DTN topology. As you can see, we operate currently four Login nodes, two Globus Online and two Special Purpose Data Transfer Nodes (DTNs), each one connected via a 100GE network link to our Data Center Network. The Data Center Network is connected via four 100GE links to the German Research Network (DFN), that are operated in a pair wise active/passive mode. The DFN then provides high bandwidth connections to the internet and via the European Research Network (Geant) to other Research Networks all over the world.

Note that the Data Transfer Nodes (DTNs) only provide server side functionality. Initiating Transfers to/from the DTNs is always done by the user from the Login Nodes or via the Globus Online Webinterface. User Login to the DTNs is not possible.

Data Transfer to/from arbitrary external sites

In the following we will outline the two data transfer methods, we currently support from/to arbitrary external endpoints.

Globus Online

The preferred data transfer method on SuperMUC-NG to/from arbitrary external sites is to use Globus Online. LRZ operates an dedicated Globus Endpoint for SuperMUC NG called LRZ SuperMUC-NG Globus DTN. In order to get started with Globus Online check out this short tutorial. Note that you can use your SuperMUC-NG credentials to log in to Globus Online and must use it to authenticate against the LRZ SuperMUC-NG Globus DTN endpoint. Just search for LRZ or Leibniz in the list of organisations on the login page(s).

In general Globus Online performs best if you transfer multiple (>8) large (>10GB) files so that it can efficiently parallelise data transfers. This is especially important over long distance links.

Secure Copy

In order to be able to transfer data to/from an arbitrary external site using Secure Copy, the IP(s) of the external endpoint(s) have to be registered as trusted IP(s) by your project in the SuperMUC-NG firewall. If not already done so, please ask the Master User of your project to submit a Service Request to register your IP(s) in the SuperMUC-NG firewall.

For smaller amounts of data you also can use secure copy (scp), secure ftp (sftp) or RSYNC (rsync) using ssh as remote shell from your external endpoint to the SuperMUC-NG login nodes. Note that the direction from external to SNG is important as the firewall of SuperMUC-NG does not permit outgoing ssh connections.

When choosing this data transfer method, please bear in mind that sshscp and sftp are very limited in the achievable performance, especially over high latency WAN links. See also on this topic.

Data Transfer to/from GCS sites

The three GCS Sites (HLRS in Stuttgart, JSC in Jülich and LRZ in Garching) operate a network of Data Transfer Nodes (DTNs), that have been optimised to enable you to transfer data with up to 10GB/s between the three German National Flagship Supercomputers. 

UNICORE File Transfer (UFTP)

UFTP is a data streaming library and file transfer tool which is based on a client/server architecture. In order to transfer between JSC, HLRS and LRZ, all three sites operate Unicore authentification services and data access servers (uftpd). To transfer files, the user has to log in to one of the corresponding hosts at the site and then authenticates with a public/private ssh key to the authentication service of another site.

At LRZ, the two authenitification services are located at

which can be both reached via the alias:

Setting up the Client

To transfer files with a client at LRZ on SuperMUC-NG to another site, you need to log in to

Then you have to load the uftp-client

module load uftp-client

For more information on the uftp-client, see the examples below or please refer to

SSH Key Management

In order to use uftp, you need to create and use seperate ssh keys. NOTE: Due to security concerns you are not allowed to use these keys for anything else than uftp transfers, especially not for SSH-based access (including SCP and SFTP) to any system. To create a new ssh key for uftp, use the following commands:

Here the transfer is to JSC, for transfer to HLRS replace "jsc"-> "hlrs"
mkdir -p ~/.uftp
ssh-keygen -a 100 -t ed25519 -f ~/.uftp/id_uftp_to_jsc

and chose a secure(!) passphrase. Keys without passphrase violate the security regulations of LRZ and their use is strictly forbidden.

Encrypted transfers

For performance reasons all data transfers are NOT encrypted by default (but authentication is, of course). If you want your transfer to be completely encrypted, use the additional command line argument "-E"  or "--encrypt" in the copy command (see also "uftp cp --help"). But be aware that this can have massive impact on the transfer speed.

Transfer between LRZ and JSC

Login to and copy the contents of ~/.uftp/ (located at LRZ) into the file ~/.uftp/authorized_keys (located at JUDAC). Now you should be able to get some informations from the uftp service at JSC by executing on skx-arch

uftp info -i ~/.uftp/id_uftp_to_jsc -u YOUR_USERNAME_AT_JSC

where you need to replace YOUR_USERNAME_AT_JSC with your username at JUDAC/JSC. The output should look similar to this:

Client identity: CN=YOUR_USERNAME_AT_JSC , OU=ssh-local-users
Client auth method: SSHKEY
Auth server type: AuthServer
Server: JUDAC
URL base:
Description: JUDAC
Remote user info: uid=YOUR_USERNAME_AT_JSC ;gid=N/A
Sharing support: enabled
Server status: OK [connected to UFTPD]
URL base:
Description: JUDAC via PRACE Network
Remote user info: uid= YOUR_USERNAME_AT_JSC;gid=N/A
Sharing support: not available
Server status: OK [connected to UFTPD]

To list the contents of a remote directory, use

uftp ls -i ~/.uftp/id_uftp_to_jsc -u YOUR_USERNAME_AT_JSC

To download a file from JUDAC to LRZ:

uftp cp -i ~/.uftp/id_uftp_to_jsc -u YOUR_USERNAME_AT_JSC /LOCAL/PATH/AT/LRZ

To upload a file from LRZ to JUDAC, you just need to reverse the order of the last two arguments:

uftp cp -i ~/.uftp/id_uftp_to_jsc -u YOUR_USERNAME_AT_JSC /LOCAL/PATH/AT/LRZ 

You can also use more streams to potentially speed up the transfer using the option "-t 10":

uftp cp -t 10 -i ~/.uftp/id_uftp_to_jsc -u YOUR_USERNAME_AT_JSC /LOCAL/PATH/AT/LRZ 

Transfer between LRZ and JSC (with client at JUDAC)

To use the client at JUDAC, please also refer to . The procedure to enable access to LRZ is similar to the one in the reverse direction:

At JUDAC create a ssh key with passphrase using

mkdir ~/.uftp
ssh-keygen -a 100 -t ed25519 -f ~/.uftp/id_uftp_to_lrz

At LRZ copy the contents of ~/.uftp/ (located at JUDAC) into the file ~/.uftp/authorized_keys (located at LRZ) and replace the authentification URL with or, so e.g.

uftp cp -t 10 -i ~/.uftp/id_uftp_to_lrz -u YOUR_USERNAME_AT_LRZ /LOCAL/PATH/AT/JUDAC

Transfer between LRZ and HLRS

To transfer from/to HLRS, create another(!) ssh key at skx-arch:

mkdir -p ~/.uftp
ssh-keygen -a 100 -t ed25519 -f ~/.uftp/id_uftp_to_hlrs

To enable the public key for transfer, open a service request at HLRS and tell them your public key (the contents of ~/.uftp/ and your username and ask them to enable your key for uftp. A sample command on skx-arch then should look like

uftp cp -t 10 -i ~/.uftp/id_uftp_to_hlrs -u YOUR_USERNAME_AT_HLRS /LOCAL/PATH/AT/LRZ 

If you encounter any problems with UFTP, please contact our Servicedesk.

Grid Community Toolkit (GridFTP)

The recommended way to transfer data between LRZ, JSC and HLRS is uftp, however, all three sites also offer a X509-Certificate based GridFTP service. To use GridFTP, you need a personal X509 certificate. If you do not have an X509 grid user certificate already, please follow the steps here:

LRZ generally provides two GridFTP Servers with the following URIs:


which can be both reached via the alias:


Associate your DN from your personal certificate with your LRZ-username

In the following we assume that you successfully obtained your signed certificate as a .p12 file which is called "SignedGridCert.p12". As a next step, you need to extract your DN (Distingiushed Name) from the certificate. This can be done via

openssl pkcs12 -in SignedGridCert.p12 -nodes | openssl x509 -noout -subject -nameopt RFC2253 | sed s/"subject="//
Enter Import Password: 
CN=John Doe,OU=Leibniz-Rechenzentrum,O=GridGermany,C=DE

Afterwards, please follow the instructions on to associate your DN with your LRZ-Account.

Until the association becomes valid it may take up to thirty minutes.

To use GridFTP with HLRS and JSC you also need to associate your DN with your corresponding usernames at these sites. For JSC, this can be done in under "Change data", for HLRS you need to contact the colleagues directly.

Getting a proxy certificate to use GridFTP

The only node to initiate transfer between the sites at LRZ is login05 also known as

After login you need to execute the following commands

mkdir ~/.globus
mv SignedGridCert.p12 ~/.globus/usercred.p12
chmod 600 ~/.globus/usercred.p12

Then you need to load the GridFTP module:

module load gridftp-client

Now you need to generate a proxy certificate with a limited lifetime. This is done via


After entering your passphrase you should have obtained a proxy certificate which is valid for several hours.

Encrypted transfers

For performance reasons all data transfers are NOT encrypted by default (but authentication is, of course). Integrity protection and encryption are optional. To integrity protect the data, use the "-dcsafe" option in the copy command. For encrypted data transfer, use the "-dcpriv" option (see also "globus-url-copy -help"). But be aware that this can have massive impact on the transfer speed.

Copying data between the sites

With your valid proxy certificate, you can copy files using "globus-url-copy". For example, to copy files from LRZ to JSC:

globus-url-copy -vb -p 6 gsi gsi

From HLRS to LRZ (note the different port 2812 in the URI from HLRS):

globus-url-copy -vb -p 6 gsi gsi 

But you can also initiate transfers from JSC to HLRS from LRZ (also on login05):

globus-url-copy -vb -p 6 gsiftp://judacsrv.fz-juelich/PATH/TO/FILE/AT/JSC gsi

For more information on the usage of globus-url-copy, see .

If you encounter any problems with GridFTP, please contact our Servicedesk.

Data Transfer to/from PRACE sites

Coming Soon.

Beyond Data Transfer: Sharing and Public Access

If you want to share data generated on SuperMUC-NG with external parties or even make this data publicly available, you can have a look at our LRZ Data Science Storage (DSS). GCS has funded 20PB of DSS storage for SuperMUC-NG. For details on how SuperMUC-NG projects can apply for storage space on DSS see: Data Science Storage for SuperMUC.