Technical Bulletins

February 13, 2014.
To improve file system reliability on the Secure Computing Facility (SCF), Livermore Computing (LC) is reducing the complexity of the SCF Lustre file system environment by moving all file systems to the same software and hardware versions, reducing the total number of file systems to four (from six), and mounting file systems from fewer clusters.

February 11, 2014.
Livermore Computing (LC) currently offers two methods for moving files from the Open Computing Facility (OCF) to the Secure Computing Facility (SCF). One method uses an electronic One Way Link (OWL), and the other uses tape technology and computer operator “sneakernet.” Moving files from the SCF to the OCF uses only tape technology/sneakernet for file transfers. There is no OWL available to transfer files from the SCF to the OCF.

October 8, 2012.
MyLC, the Web-based high performance computing portal for Livermore Computing (LC), has been enhanced since its initial release last year. For regular users of MyLC, the enhancements are highlighted below, and for those who have not used MyLC, the information herein serves as an introduction.

November 7, 2011.
The MyLC dashboard, part of the Lorenz effort, is now available to all LC users in both the OCF (CZ and RZ) and SCF. Lorenz aims to simplify users’ HPC experience by leveraging modern Web application technologies. The MyLC dashboard is the first step in reducing tedious and awkward tasks associated with HPC and providing access to key HPC tools and information.

October 20, 2011.
It is Livermore Computing (LC) policy that user directories may not have world read, write, or execute permissions set to allow all users the ability to view, modify, or execute files contained in them. To enforce this policy, LC will monitor the permissions on top-level directories in the following file systems:

September 26, 2011.
To address the need for Restricted Zone (RZ) users to move data between their desktops and the RZ, Livermore Computing (LC) has deployed a machine named rzstage that allows easy and secure file transfers using SCP or SFTP between RZ users’ desktop machines in the LLNL Enterprise Network and file systems mounted in the RZ.

August 10, 2011.
Livermore Computing (LC) is continuing the process of moving its Open Computing Facility (OCF) resources from the LLNL Enterprise Network (EN) into a multi-zone High Performance Computing (HPC) Enclave. This Technical Bulletin contains brief background information about the HPC Enclave, provides the current schedule of important upcoming events, and answers some frequently asked questions that LC has received during customer meetings and briefings.

August 3, 2011.
The creation of the High Performance Computing (HPC) Enclave will necessitate restricting Restricted Zone (RZ) users from executing code or scripts from a Lustre file system when on an RZ compute platform. All executables must be from either the RZ users’ /g/g* home directory or other RZ file systems such as /nfs/tmp2, /usr/gapps, /usr/local, or /usr/global.

May 16, 2011.
This bulletin details major changes to the Open Computing Facility (OCF) that will be made during the next five months as Livermore Computing (LC) moves toward supporting a Livermore Valley Open Campus.

February 2, 2009.
Most CHAOS 4 machines—Atlas, Eos, Hera, Juno, Minos, Rhea, and Zeus—use NAT (network address translation) for their internal compute nodes. These internal nodes do not have accessible network interfaces to outside machines. Outward bound connections are sent to a routing node, and NAT changes their apparent IP address. Because they can not effectively communicate in both directions with the external world, storage tools will not work on these internal compute nodes. Storage tools have not worked properly on these machines since their installation. With the incorporation of iorun into these tools, batch jobs can access storage.

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