CERN Accelerating science

This website is no longer maintained. Its content may be obsolete. Please visit http://home.cern/ for current CERN information.



next up previous
Next: Migration of VM Up: VM Migration Issues Previous: VM Migration Issues

Downsizing and Closure of the CERNVM Service

  Miguel Marquina CN/DCI and Harry Renshall CN/PDP

The CERN Management Board has now approved the time scale for the end of the CERNVM service. The computing capacity will be reduced by half during the Christmas shutdown at the end of 1995 and the service will be terminated on 30 June 1996. From January a clear warning message of the termination date will be displayed when a user logs in. Various aspects of this timescale are discussed below.

Plans for Hardware Reductions at the End of 1995

Currently the machine has six CPUs (Central Processing Units), each rated at 10 CERN Units, with 512MB of real and 512MB of extended memory. This supports its current load of an average of about 650 users logged in during working hours, using from 20 to 25% of the CPU cycles, and about 50 different users per week running batch jobs which take from 40 to 60% of the cpu cycles.

During the end-of-year shutdown three CPUs and half of the real and extended memory will be removed. In addition many external peripherals will be removed as the number of such devices that can be supported is coupled to the number of CPUs. We anticipate that there will be a small but noticeable degradation in the interactive response times, largely due the reduction in memory. The policy on batch work is that only that authorised by the COCOTIME committee will be permitted, with priority going to the few older experiments that expect to terminate ahead of the final CERNVM shutdown. We will not run any very long batch jobs other than for named individuals from these experiments or those CERN groups with projects that are also terminating their work on CERNVM.

Hardware that is being removed includes the disk strings belonging to the Aleph experiment (these have been unmaintained for over a year), all of the SMCF (low density cartridge robot) tape drives and 6 of the 10 manual 3480 tape drives (see below).

CERNVM will be in a position to offer a limited service on all its existing tape devices while users convert to the alternative services.

Removal OF SMCF Robot

As has been previously announced, MEDDLE/COLLECT agreed that the IBM 3495 robot SMCF (200 Mbyte volumes) will be switched off and removed at the time of the Christmas shutdown. The approx 16,800 volumes that it contains will have to be relocated, either in the manual racks or in the archive store. Due to the amount of work involved in rearranging the manual racks, we would prefer to archive as many of these volumes as possible, along with as many volumes as possible from the manual racks where they would be going in order to liberate space for them. It should be noted here that even though some archiving has taken place during 1995, the volume of dearchiving has been such that the overall occupation of the vault has not varied very much. Space MUST be liberated in order to make room for the foreseen reprocessing of LEP data and users should also consider copying this data to (for example) DLT volumes with a 50:1 reduction ratio in order to progressively eliminate the 3480 volumes before the 3480 drives become too difficult to access.

Some 2,000 volumes in the Innnnn series which have not been used for more than two years, will certainly be archived unless their owners can convince us of the need to keep them active. Details of the volumes in this robot can be found in WWW at:

http://wwwinfo.cern.ch/pdp/vm/guide/SMCF_LIB.HTML

and, in particular, 'archive candidates' can be found in SMCF_ARC.HTML.

Manual 3480 Drives and Robot Capacity

During 1996, the number of 3480 manual drives is likely to be reduced by up to 50% to save maintenance costs. It may be that the 16 drives from SMCF, being the most modern, will be kept and all the others removed. In any case, users are strongly recommended to concentrate their tape activities on denser media, DLT or IBM 3590 and transfer larger amounts of data per mount as there will be a shortage of manual mounting capacity. We have ordered extension units for the TL820 DLT robot and more 3590 drives and cartridges are also due to arrive soon, so our robotised capacity will not be reduced by the departure of the approx 3 Terabyte SMCF, but will be increased by 10 Terabytes in the DLT robot and about 22 Terabytes in the 3494.

Reduction of Shift Cover

In July 1996, the number of shift operators available for manual mounts will be reduced to one person per shift, effectively reducing by 1,000 the number of mounts that can be performed in one day.

Choosing your Service to Replace CERNVM

We receive often the question: now that CERNVM is going, to where should I move? In recent Computing Newsletters you have read about the new Central Services being deployed by CN Division, but probably you nevertheless felt a need for an overview showing which of them would be the most convenient for you.

Currently we offer two distinct working environments: the Unix-based CUTE/CORE Service and the PC-based NICE Service.

Unix-based

The first of these services, CUTE/CORE, has been set up and built around the needs of scientific computing: large CPU capacity, intensive I/O processing including access to magnetic media, and a general interactive environment which allows the preparation, execution and verification of physics data-processing tasks. This includes of course a solid software programming environment (Fortran, C, C++, debuggers, etc). You may find, as well, software for Text Processing (LaTeX, FrameMaker ), editing (nedit, emacs, pico ), printing (xprint ), access to WWW (Mosaic, Netscape, Lynx ), preparation of presentations (xfig, webslider ), etc.

This environment is today the one of choice for physicists, engineers and programmers, and for anybody else whose basic work is centered around computational tasks.

The services that you may access in this context are:

The CORE SHIFT servers are dedicated to individual experiments who internally decide how to share the resources. The batch resources of the CERNSP and CSF services are allocated by the COCOTIME committee. If you require to run batch work on either, contact your group administrator to find out what budget your group has been allocated or how to request an allocation.

PC-based

The second service, NICE, proposes a different working model. It brings together all the traditional desktop applications (Word, Excel, Project , drawing packages) which are useful in administrative tasks and in the preparation of all kinds of documents. It delivers as well CAD/CAM and other project design tools of use to the engineering community. And, finally, it allows access to the Unix Services if required (through the usage of special connectivity software).

If you are an engineer involved in the design phase of a CERN project, or perform duties of an administrative nature, a PC served by the NICE environment is the answer to your needs.

The articles gif, gif, gif and gif, present you in more detail both environments, so that you may reach a better assessment on which is more suitable to you. If you are still unsure, please feel free to come along and discuss your needs with any of us, either at the UCO or directly to the authors of the articles below on the NICE and CUTE architectures.

Migration from CERNVM

The end of CERNVM is now fixed for 30 June 1996. Users can already register on the new services but several key elements mean we do not recommend most users to start moving until January 1996 while we stabilise various new interfaces, described in separate articles below. These include bringing into service a mail server which will act as a CERN-wide, system-independent mail handler. Users will automatically be registered on this server when they receive their first AFS account registration from January. Other elements that will be in place from January include commands to copy easily user VM files into a user's Unix AFS space, a Unix file archive command using the IBM ADSM product mentioned in the next article, better availabilty of scratch space, a graphical interface version of the VM 'copytape' command, the 'userreg' registration command, the 'runacc' command for group accounting and a packaged interface into the Tape Management System (TMS) for group administrators. It is intended to move the TMS database from CERNVM to a Unix platform during the Christmas shutdown and provide a transparent interface for CERNVM TMS commands. Groups should plan to migrate their TMS administration work to Unix as soon as the new tools are available. In addition, many heavily used corridor IBM3812 printers will have been replaced with new network based printers (see section gif). Groups with queries about their IBM3812 printers should contact D.J.Underhill, head of CN/CIO Group.

Note that user Unix training seminars and tutorials are already being given by CN division (see section gif) and these will continue during next year. The Unix services also include a set of tools, such as 'rexx' and 'vmedit', a simulation of 'xedit' on CERNVM, which are not recommended for long term use but rather to spread out the need to learn new techniques over a longer time.



next up previous
Next: Migration of VM Up: VM Migration Issues Previous: VM Migration Issues



Michel Goossens
CN Division
Tel. 3363
Tue Nov 28 18:14:41 MET 1995