Old policies page

Policies for Computer Users

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.

Temporary Allocation

Effective Monday, April 12, at noon, we will move to a fixed allocation of nodes to users. To promote efficient usage, some nodes are shared between two users. We hope sharing with a single other user will be easier to coordinate, and please try to do so equitably.

These allocations in no way preclude flexibility: users should simply e-mail the owner and ask permission to use idle nodes.