Table of Contents
This documentation describes how multiple users can share data within SCC.
There are currently 4 options we offer, described below.
Using a hidden directory
In this case the data will be available for reading by all users or by a specific POSIX group only if they know the path to it. You should send the path to users whom you want to give the access. In order to make it safer, better to share data via
First you need to create a directory with a random name
SHAREDIR=$(mktemp -p /scratch/users/$USER -d share.XXXXXXXX)
This will create a directory with a random name in
/scratch/users/$USER and save the path in the variable
Now you can copy or move the files you want to share in that directory:
cp /PATH/TO/MY/FILES $SHAREDIR/. # if you want to copy mv /PATH/TO/MY/FILES $SHAREDIR/. # if you want to move
Now you need to set permissions to the directories:
chmod go=x /scratch/users/$USER # will set an execute permission on the parent directory chmod -R go+rX $SHAREDIR # will make the files readable for other users and the group
After that send the path to users you want to share data with. To print the path of the shared directory run:
The users who know the path can
cd into it and copy the files contained in the directory.
After sharing is done, don't forget to unset execute permission of the parent directory to restrict the access to files again.
chmod go= /scratch/users/$USER # will unset all permissions on the parent directory
Project directory in scratch filesystem
In this case we will create a shared project directory in scratch filesystem (
/scratch/projects/PROJECTNAME) and give the full access to it for users of a POSIX group of your choice. This option is good for collaboration where huge amount of data is involved. Be aware that the scratch filesystem doesn't have a backup. If you want a backup, you can consider the next option.
Applying for a group
In order to share the directory with a group of users you need to apply for a POSIX group by contacting us. Please give us a unique group name and usernames of people you want to be in the group.
In this case you will have a
HOME directory of the functional account as a shared space for collaboration like in the previous option. It comes with a backup and archiving possibilities, however, the IO performance for large computations will be affected by slow
HOME filesystem, if you will need to process a large amount of data, please consider the previous option or both options simultaneously, by using a functional account for storing data and the scratch filesystem for processing.
First you need to apply for the functional account, which will take some days, since it should be approved by the head of your institute. Then you need to apply for the POSIX group as described in the previous section. When you have the access to you functional account, contact us, so we can add your functional account to the POSIX group.
After the POSIX group is ready, change the permissions of the
HOME directory on the login node (login.gwdg.de):
ssh firstname.lastname@example.org chmod g+rwxs . # everyone in the group will have all access rights to the directory chgrp YOURGROUP . # change the group of the Home directory
If you don't want members of the group to be able to delete or rename the files that don't belong to them, you can add a sticky bit to it with
chmod g+t .
In this case you first need to get an S3-Bucket from us. In order to get an S3-Bucket you can simply write a Mail to email@example.com and ask for one, which is accessible from the HPC system. You can then share your
secret key and
private key within your group to give everyone access. In this scenario, access to your data is done via http and it is reachable not only from the HPC system, but also from the Cloud and Internet (if needed).
You can access your S3-Bucket from a compute node using
http://172.19.1.26:8090 as an endpoint.
In order to work with your S3-Bucket, you could for instance use
module load rclone # List content of your Bucket rclone ls <config-name>:<bucket-name>/<prefix> # Or Snyc the Content of your $HOME with the Bucket rclone sync -i $HOME/some/folder <config-name>:<bucket-name>/<prefix> # Or Snyc the Content of your Bucket with your $HOME rclone sync -i <config-name>:<bucket-name>/<prefix> $HOME/some/folder
This requires a config file in
/usr/users/$USER/.config/rclone/rclone.conf with the following content:
[<config-name>] type = s3 provider = Ceph env_auth = false access_key_id = <AccessKey> secret_access_key = <SecretKey> region = endpoint = http://172.19.1.26:8090 location_constraint = acl = server_side_encryption = storage_class =