Network drives (H:, N:, S:)

When you log in to Esrum for the first time, your home folder should contain a (link to a) single folder named ucph. This folder in turn contains (links to) your UCPH network drives:

• ~/ucph/hdir: The H-drive (H:) is your personal drive for storing data that is not shared with anyone else. This may include personal and confidential data.

• ~/ucph/ndir: The N-drive (N:) is used shared data that is neither personal nor confidential. You will have access to any number of sub-folders depending on your affiliations, including the SUN-CBMR-Shared-Info folder containing files shared across the entire center.

• ~/ucph/sdir: The S-drive (S:) is meant for sharing of sensitive and personal data with other employees at UCPH. For more information, see the official documentation.

Tip

You can also access your network drives online via https://webfile.ku.dk/.

Limitations on network drives on Esrum

By default, these network drives are only accessible from the head node, and access is furthermore limited to about 10 hours after you logged in. Additionally, these drives may not be available if you do not log in by typing your password.

It is therefore recommended to always copy data that you are working to the corresponding /projects folder. If you don't have a /projects folder, then see the Requesting projects and datasets page for instructions on how to request a new project. Never store data in your home folder and remember that projects have to be audited (indicated by the -AUDIT suffix) if you are working on sensitive/GDPR-protected data.

Should you be missing any of these folders, or should you be unable to access the folders from the head node, then please see the Troubleshooting section below.

Accessing network drives from compute nodes

To access network drives from compute nodes and from RStudio sessions, you first need to authenticate as described in the (Re)activating access to the network drives section below. Once you have done so, you can access the network drives at their canonical locations:

Drive	Location
H:	/maps/hdir/${USER}
S:	/maps/sdir/${USER}
N:	/maps/groupdir/${USER}

The variable ${USER} refers to your username, in the form abc123. Note that the same time-limits apply, as when accessing the network drives from the head node. These paths work on the head node, on compute nodes, and on the RStudio nodes, provided that you have authenticated as described below.

(Re)activating access to the network drives

Should your login have timed out, should you have logged on to Esrum without having entered your password, or should you be connected to a compute node or an RStudio server, then the network drives may be inaccessible. This will typically result in No such file or directory errors when attempting to access files/folders on the network drives.

To (re-)authenticate and thereby enable access to the network drives, run /usr/bin/kinit and enter the password for your UCPH account:

$ /usr/bin/kinit
abc123@UNICPH.DOMAIN's password: ************
$

This command must be run on the server from which you wish to access the network drives:

• From the head node: Simply run /usr/bin/kinit while connected to the head node.

• From a compute node: Start an interactive session as described in the Interactive sessions section, and then run /usr/bin/kinit. You will then be able to access the network drives in that session.

• From an RStudio server: Log in to the RStudio server as described on the RStudio page and open the Terminal tab. Run the command /usr/bin/kinit in that terminal.

Warning

The explicit path in /usr/bin/kinit is required to make sure that you call the correct executable, even if you are using a Conda environment or similar. Running kinit without the full path may otherwise result in errors like kinit: Unknown credential cache type while getting default ccache.

Once you have successfully run /usr/bin/kinit, you should be able to access the folders under ~/ucph (only on the head node), or at their canonical locations (see Accessing network drives from compute nodes). However, if you have tried to access these folders within the last few minutes, before running /usr/bin/kinit, then you may have to wait a few minutes before the folders become accessible again.

Extending your access to the network drives

The maximum duration of your current session (Kerberos ticket) is about 10 hours, and the time at which it expires can be viewed via the command /usr/bin/klist:

$ /usr/bin/klist
Ticket cache: KEYRING:persistent:436828696:krb_ccache_nBciOlx
Default principal: abc123@UNICPH.DOMAIN

Valid starting       Expires              Service principal
07/29/2025 11:22:49  07/29/2025 21:22:49  krbtgt/UNICPH.DOMAIN@UNICPH.DOMAIN
    renew until 08/03/2025 21:55:43

In this case the current session expires at 07/29/2025 21:22:49, but you can renew it for another 10 hours, until the time specified on the renew until line.

To renew your session, use the /usr/bin/kinit -R command. Unlike the basic /usr/bin/kinit command, this does not require that you enter your password:

$ /usr/bin/kinit -R
$ /usr/bin/klist
Ticket cache: KEYRING:persistent:436828696:krb_ccache_nBciOlx
Default principal: abc123@UNICPH.DOMAIN

Valid starting       Expires              Service principal
07/29/2025 12:44:10  07/29/2025 22:44:10  krbtgt/UNICPH.DOMAIN@UNICPH.DOMAIN
 renew until 08/03/2025 21:55:43

If /usr/bin/kinit -R fails with the message kinit: No credentials cache found while renewing credentials, then you are not authenticated and need to run /usr/bin/kinit without the -R as described in (Re)activating access to the network drives.

Troubleshooting

The ~/ucph folder or subfolders are missing

Note that the ~/ucph folder is only available on the head node (esrumhead01fl), and not on the RStudio servers nor on the compute nodes. See the Accessing network drives from compute nodes section for how to access the drives elsewhere.

If you are connected to the head node, then firstly make sure that you are not using GSSAPI (Kerberos) to log in. See the Connecting to the cluster page for instructions for how to disable this feature if you are using MobaXterm.

Once you have logged in to Esrum without GSSAPI enabled, and if the folder(s) are still missing, then run the following command to create any missing network folders:

$ bash /etc/profile.d/symlink-ucphmaps.sh

Once this is done, you should have a ucph symlink in your home folder containing links to hdir (H:), ndir (N:), and sdir (S:).

No such file or directory when accessing network drives

If you get a No such file or directory error when attempting to access the network drives (~/ucph/hdir, ~/ucph/ndir, or ~/ucph/sdir), then please make sure that you are not logging in using Kerberos (GSSAPI). See the Accessing network drives via MobaXterm section for instructions for how to disable this feature if you are using MobaXterm.

Note also that your login is also valid for about 10 hours, after which you will lose access to the network drives. See the section (Re)activating access to the network drives for how to re-authenticate if your access has timed out.

kinit: Unknown credential cache type while getting default ccache

The kinit command may fail if you are using a conda environment:

(base) $ kinit
kinit: Unknown credential cache type while getting default ccache

To circumvent this problem, either specify the full path to the kinit executable (i.e. /usr/bin/kinit) or deactivate the current/base environment by conda deactivate.