Storages


DCC Storage Groups

Within DCC we offer multiple levels/types of storage of varying capacity/usage.


Home

Current capacity 44Tb

This storage is, by default, available to all staff and students as your Linux “home” directory, i.e. the one that you see when you connect to Linux systems within the HPC environment (e.g. login.gar.dtu.dk or login.hpc.dtu.dk)

It is also accessible to non Linux users via SAMBA:

Windows \\home.cc.dtu.dk\username
MAC smb://home.cc.dtu.dk/username

This is backed up to tape, and space is limited thus quotas are enforced on all home directories. Space here should be used for important data, documents, source code, and output results etc.

Default quota is 30Gb

Check current usage of all directories:

du -sk .[!.]* * | sort -n

Scratch filesystems

Current capacity 62TB + 98TB

This is allocated on a request basis. We have two shared high performing (I/O) parallel file system between all HPC nodes and it offers Low-Latency and High Speed connectivity via an Infiniband network. This should be treated as temporary storage for the duration of HPC jobs. It is accessible from HPC nodes as /SCRATCH/<username> and /work1/<username>

**** Please remember that our scratch-filesystems are not backed up ****

Capacity and performance of the scratch file system increases by adding more storage “nodes”. The concept is that departments with several heavy users are expected to contribute to the storage pool.

Users can easily check their scratch usage with a dedicated command.


iRODS

Current capacity 170Tb

Irods is used for special group/departmental projects to store and manage large data sets. Current project test phase does not include tape back/archiving.

DCC iRODS user guide


Technical Information

For those interested in the underlying technical information…

We are using ZFS for home, this offers certain benefits including hardware redundancy in the RAID setup, daily snapshots of data (quicker data recovery), snapshot replication to secondary server.

Scratch is a Distributed file systems utilising BeeGFS connected via an infiniband network to the HPC cluster nodes.


External Links

iRODS
Infiniband / BeeGFS
ZFS / NFS / SAMBA