Policies

In order to efficiently use our computational resources, we ask all group members to follow the guidelines below when planning and running simulations:

• Please run jobs on the computational nodes ("slave nodes"), rather than the head node, of each cluster. In the past, head node crashes – a great inconvenience to everyone – have occurred when all eight of its processors are engaged with computationally intensive work.
• Please do not "run jobs on top of" those of other users. If a node is fully occupied and you need to run something, please contact the other user, rather than simply starting your job there.
• For fastest disk read/write speeds, write the to local /scratch/username/ directory on each node, rather than your home directory. Home directories, which are accessible from every node, are physically located on the head node, so that reading and writing to disk may be limited by network transmission rates.
• The new cluster, with its fast interconnection hardware, is very well suited for large-scale simulations which benefit from the use many processors. A queuing system will be used to manage jobs on this cluster, and no jobs should run outside this queue system.

Please note that we attempted to implement the OpenPBS queue system on Cyrus1 and Quantum2 in December 2009; these systems appeared to be working in testing, but did not perform as desired when multiple jobs were submitted. The use of these queuing systems on those clusters has been suspended until further notice.

Computer Clusters

Darius

Darius is our newest cluster, with 30 computational nodes, each with 8 virtual processors.

Cyrus1

Hostname: cyrus1.csbi.mit.edu
Cyrus1 is a 24-node cluster, installed December 2008.

Please note that the CSBi network, on which Cyrus1 is hosted, does not allow access from IP addresses external to MIT. For remote access to Cyrus1, see the MIT IST VPN site.

Status notes

Node 10 (n010) is currently inaccessible.

Node information

The table below lists the memory and swap file size of each node on Cyrus1, along with the amount of space used and free in each node's local /scratch/ directory. This information is current as of April 1, 2010.

Quantum2

Hostname: quantum2.mit.edu
Quantum2 is a 20-node cluster installed in October 2007, which features high-memory nodes for quantum-chemical calculations.

Status notes

Nodes 4 and 14 (n004 and n014) are currently inaccessible, due to apparent hard disk problems.

Node information

The table below lists the memory and swap file size of each node on Quantum2, along with the amount of space used and free in each node's local /scratch/ directory. This information is current as of April 1, 2010.