SHIFT Software Evolution: CASTOR

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SHIFT Software Evolution: CASTOR

Jean-Philippe Baud , IT/PDP

In January 1999 CERN began to develop CASTOR ("CERN Advanced STORage manager"). It is an evolution of SHIFT, which has been used at CERN for all experiments in the 1990's. CASTOR is more scalable than SHIFT and should be able to handle data for the overlapping run of the NA48 and COMPASS experiments, the latter starting in 2000. Scalability issues are solved by using multi-threading and database technology instead of a flat file for the stager catalog. The first tests show that we get for the first time the full bandwidth of the drives and of the network. The software can be installed on any platform running Unix or Windows/NT.

New features:

better resilience, better immunity to network hiccups
general use of APIs (Application Programming Interfaces) to avoid command line size limitations
better load balancing of the requests between Tape Servers
tapes are not dismounted if other requests are waiting for them
basic Hierarchical Storage Manager facility.
- The physicists can choose to work either explicitly with tapes, as with SHIFT, or reference files by name:
  - global name space implemented through a Name Server
  - automatic tape volume allocation
  - explicit migration and recall of files

Current status:

The Tape Server software, the new stager with its new Database Server and the Name Server are being extensively tested. The Tape Volume Allocator is under development.

See URL: http://wwwinfo.cern.ch/pdp/castor/

Deployment:

The CASTOR User Interface is fully backwards compatible with SHIFT and the product itself is very modular, so we will be able to put it in production component by component over the winter 1999/2000. The new stager will be tested in January by one of the LEP experiments. The introduction of the software will be done experiment by experiment with their approval, but the goal is to have all experiments running the new software before the accelerator startup.

A "Data Challenge" test (7 days at 100MB/s sustained, i.e. around 60TB) will be attempted for ALICE in February or March 2000.

Note: A possible common approach for the future of the Data Management software in HEP is currently being discussed by the major HEP institutes.

For matters related to this article please contact the author.

Cnl.Editor@cern.ch

CERN Accelerating science

SHIFT Software Evolution: CASTOR

New features:

Current status:

Deployment: