Introduction of Production Services on the SP2 (CERNSP)
Tony Cass CN/DCI and Harry Renshall CN/PDP
The CERNSP service is now in production for physics applications such as raw data analysis, DST production, DST analysis, Monte Carlo event generation and program development. This service is intended primarily for experiments which do not have independent CORE or Work Group Server capacity though, being public, there are no restrictions on which users or groups can have accounts. Allocation of CERNSP resources will be done by the Cocotime committee and it is intended to start the usual monitoring and control from 1 April. Only batch time will be budgeted, representing just under half of the total capacity. About ten times as much CPU time is available than on the current CERNVM service; we do not anticipate it will be full of approved work initially and thus there will be some free time available on a non-guaranteed basis. Note that the main Monte Carlo event generator service is the CSF cluster, currently awaiting a 50% capacity upgrade.
We have enabled all groups which have any CERNVM accounts to be able to register accounts on CERNSP. A group administrator who already can register accounts on CERNVM can now also register on CERNSP. On entering USERREG they should first select the CUTE general service then CERNSP out of the second list presented. Groups without such an administrator should contact Attila Koppanyi, Attila.Koppanyi@cern.ch, stating who should be enabled to register on CERNSP (this must come from a group computing contact or an existing administrator). Groups should also nominate an AFS Space Administrator as the SP2 users, like those on existing Work Group Servers, have an AFS rather than a local home directory. Again, A. Koppanyi should be contacted to register, or provide a guide for, the AFS Space Administrator. Finally groups should submit to Alan Ball, AEB@CERNVM, the Cocotime secretary, their CERNSP computer time requests for the last three quarters of 1995.
The SP2 is a 64-processor Unix system using IBM RS/6000 nodes linked by an internal high speed network and with a centrally managed software environment. The nodes are functionally divided into four groups of 16 each for different types of work namely interactive logins, sequential job batch processing, parallel job batch processing and data, tape and network services. Each node is rated at 25 CERN units (the six nodes of CERNVM are each 10 units).
Access to the interactive nodes is via the single name CERNSP which uses a load balancing mechanism to distribute users among the 16 interactive nodes. Either telnet to CERNSP or use an X-terminal login window to connect. Users from outside CERN will need to use the fully qualified name, cernsp.cern.ch. All SP2 accounts have their home directory space in the CERN AFS file system which means that password changing is done using the kpasswd command. Your password and files are common to any CERN computer which is connected to the CERN AFS system. A feature of this is that you must renew what is termed your AFS token, given to you at login, each 24 hours else you lose access to your files. To renew your token either systematically logout at the end of your work or type klog when you start each morning. A user guide to AFS is available from the User Consultancy Office and help fs shows the afs commands available.
Batch work is run under the control of the IBM Loadleveler product, so batch job scripts are submitted via the llsubmit command and the queues can be seen via llq (type man command as approporiate). This system returns files to a job subdirectory created under the submitted batch job script file with a different number for each job. Job times are specified, and given in accounting reports, in CERN Units. The command llclass returns the current job class definitions. The IBM Loadleveler User's Guide is available on request from the UCO. Tape access is via the STAGE commands documented in the two guides ``An Overview of the CORE Computing Services'' and ``A Reference Manual for SHIFT Software'', also to be found in the UCO.
The Fortran compiler is the IBM xlf product. This is a full Fortran 90 compiler with a Fortran 77 language level which is the default. By default it compiles at a low optimisation, an important slow-down, and without appending an underscore to external references as required for the CERN Program Library. We have hence made a front end to xlf, called hepf77, which supplies sensible defaults. You can obtain copies of the xlf User's Guide and Reference from the UCO either by purchasing the IBM manuals or asking for the locally printed copies (much bulkier and without colour).
As an aid to migration from VM, many familiar VM tools have been migrated to Unix and are available on CERNSP. They can be executed with their usual names prefixed by the letters ``vm'', e.g. vmxedit, vmrexx, vmnews or, by executing a command, aliases that do not need the vm prefix can be built. Type man vm on CERNSP for information on these tools and for practical advice on user level differences between CERNVM and Unix.
A new news-group,
has been created for items specifically
about the CERNSP service, though users should also look at the
cern.computing groups. Urgent messages relevant to the
are issued through the Zephyr system. This sends messages to subscribing
users wherever they are logged in if the Zephyr client, zwgc, is started.
(The workstation also needs to be running the Zephyr host manager; this is
configured on the CERNSP and other Work Group Servers.) If you are
interested in receiving messages about the CERNSP service you should
subscribe to the CERNSP Zephyr class with the command
zctl subscribe cernsp * *''.
The Zephyr client is started automatically for users
connecting to the CERNSP with an xdm login session from an X-terminal
with a subscription to the CERNSP class.
Further details about Zephyr are given in the ``Zephyr at CERN'' guide available from the UCO and additional information about the CERNSP service can be found in the WWW system at the URL:
Some parts of the CERNSP World Wide Web pages, are also available in printed form at the UCO as the CERNSP Introductory User Guide.