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SHIFT Software Evolution: CASTOR
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
- 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
- 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
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.
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
A "Data Challenge" test (7 days at 100MB/s sustained, i.e.
around 60TB) will be attempted for ALICE in February or March
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.
Last Updated on Thu Dec 16 13:32:54 GMT+03:30 1999.
Copyright © CERN 1999 -- European Laboratory for Particle Physics