Holodeck Nodes

The Holodeck cluster consists of 24 work nodes and 2 head nodes. The purpose of this page is to give an overview of the available nodes, their hardware and on how to access them. Also the purpose of the two classes of nodes – head nodes and work nodes – will be explained in greater detail.

Note that all nodes run on UTC time.

Head nodes

The purpose of the head nodes is mainly to handle logging into the cluster and handle storage. They are however capable machines that can be used to quickly test code before sending it to the work nodes.

The nodes have the names

• holodeck1

• holodeck2

and are accessible through

gsissh <name>.aei.uni-hannover.de

where <name> needs to be replaced by one of the names from the list above.
All head nodes have the same hardware specifications, which are (per node):

CPUs:

• 2x Intel Xeon E5-2640v4 (10 cores, 20 threads @ 2.4 Ghz base clock/3.4 GHz boost clock)

RAM:

• 256 GB TruDDR4 (PC4-19200 CL17 2400MHz LP RDIMM)

Network:

• Mellanox SX6036 FRD14 Infiniband Switch (and according cables)

Storage:

• 2x SSD (120 GB) not accessible by users

• 10x HDD (8TB, 12 Gbps) accessible through different paths (see wiki-page on file structure)

GPU:

• None

Work nodes

The purpose of the work nodes is to run code over long periods of time (i.e. code with long run time). If you want to run your code on these nodes please use the job-scheduler slurm and refer to its wiki-page for instructions on how to use it.
The work nodes can be accessed directly through the head nodes. This is however not meant to be a way of executing code on a specific machine but rather a way to monitor what your code is doing.

To log onto the work nodes you need to have an ssh-key setup and than type

ssh nr<x>

Replace <x> by one of the number associated to the work node you are trying to log onto. Number can be 01 to 24. Please note that for nodes 1 to 9 you need to type the leading zero, i.e. to log onto the first work node type

ssh nr01

The hardware of all work nodes is the same with the following specifications

CPUs:

• 2x Intel Xeon E5-2698 v4 (20 cores, 40 threads @ 2.2 Ghz base clock/3.6 GHz boost clock)

RAM:

• 256 GB TruDDR4 (PC4-19200 CL17 2400MHz LP RDIMM)

Network:

• Mellanox Connect-IB FDR IB Single-port (and according cables)

Storage:

• 1x HDD (1TB, 6Gbps) (see wiki-page on file structure)

GPU:

• None

See also

File structure on Holodeck · slurm · List of installed software

-- MarlinSchFer - 17 Apr 2019