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Cluster Compatibility Mode is now available on Hopper

April 10, 2012

We are pleased to announce a new feature on Hopper, Cray Cluster
Compatibility Mode (CCM) which allows applications that previously could
only run on Carver to run on Hopper.

Cluster Compatibility Mode (CCM) is a Cray software solution that
provides services needed to run most cluster-based independent software
vendor (ISV) applications on the Cray XE6. It supports the standard
Linux services, such as ssh, rsh, nscd, and ldap, and complete root file
systems on the compute nodes (therefore supports dynamic shared
libraries). With CCM, the applications that couldn't run on Hopper due
to the lack of TCP/IP support now can run on Hopper. The Gaussian (G09),
NAMD replica simulation, and WIEN2k codes are the applications that are
enabled on Hopper recently through CCM. Additionally, CCM enables serial
workloads to run on Hopper.

You can access CCM through the ccm_queue on Hopper. Due to the slower
processor speed on Hopper (2.1GHz) you may find applications run slower
on Hopper CCM when compared to Carver (2.7GHz), however, we expect the
queue wait time to be shorter, which we hope will give users the
incentive to try CCM. We have also created a new queue ccm_int, which
has the same queue priority as the debug/interactive queue, to
accommodate the interactive CCM workloads, eg., debugging, data
analysis. Currently the applications and tools available for CCM are
g09, namd_ccm, wien2k_ccm, matlab_ccm, ipm_ccm and ddt_ccm. For more
information about CCM and how to use it on Hopper, please visit our
website at,

If you have been limited by the lack of the TCP/IP support on Hopper
computing environment in the past, you are encouraged to try out CCM on
Hopper. CCM is a new product of Cray, and it is still in the
experimental stage. Your feedback and comments are especially welcome.