Narval

Availability: October, 2021

Login node: narval.computecanada.ca

Globus endpoint: computecanada#narval-dtn

Data transfer node (rsync, scp, sftp,...): narval.computecanada.ca

Narval is a general purpose cluster designed for a variety of workloads and situated at the École de technologie supérieure in Montreal. The cluster is named in honour of the Narwhal, a species of whale which has occasionally been observed in the Gulf of St. Lawrence.

Site-specific policies

By policy, Narval's compute nodes cannot access the internet. If you need an exception to this rule, contact technical support with information about the IP address, port number(s) and protocol(s) needed as well as the duration and a contact person.

Crontab is not offered on Narval.

Each job on Narval should have a duration of at least one hour (five minutes for test jobs) and you cannot have more than 1000 jobs, running and queued, at any given moment. The maximum duration for a job on Narval is 7 days (168 hours).

Storage

HOME Lustre filesystem, ~100 TB of space	Location of home directories, each of which has a small fixed quota. You should use the project space for larger storage needs. 50 GB of space and 500K files per user. There is a daily backup of the home directories.
SCRATCH Lustre filesystem, ~5 PB of space	Large space for storing temporary files during computations. No backup system in place. 20 TB of space and 1M files per user. There is an automated purge of older files in this space.
PROJECT Lustre filesystem, ~15 PB of space	This space is designed for sharing data among the members of a research group and for storing large amounts of data. 1 TB of space and 500K of files per group. There is a daily backup of the project space.

For transferring data via Globus, you should use the endpoint computecanada#beluga-dtn, while for tools like rsync and scp you can use a login node.

High-performance interconnect

The InfiniBand Mellanox HDR network links together all of the nodes of the cluster. Each hub of 40 HDR ports (200 Gb/s) can connect up to 66 nodes with HDR100 (100 Gb/s) with 33 HDR links divided in two (2) by special cables. The seven (7) remaining HDR links allow the hub to be connected to a rack containing the seven (7) cental HDR InfiniBand hubs. The islands of nodes are therefore connected by a maximum blocking factor of 33:7 (4.7:1). In contrast, the storage servers are connected by a non-blocking network.

In practice the Narval racks contain islands of 48 ou 56 regular CPU nodes. It is therefore possible to run parallel jobs using up to 3584 cores with a non-blocking network. For larger jobs or ones which are distributed in a fragmented manner across the network, the blocking factor is 4.7:1. The inter-connect remains a high-performance one nonetheless.

Node Characteristics

nodes	cores	available memory	CPU	storage	GPU
1109	64	~256000M	2 x AMD Rome 7532 @ 2.40 GHz 256M cache L3	1 x 960 GB SSD	-
33		~2048000M
158	48	~512000M	2 x AMD Milan 7413 @ 2.65 GHz 128M cache L3	1 x SSD of 3.84 TB	4 x NVidia A100 (40 GB memory)

Globus is a file transfer service