  MAGIC-I is currently the Imaging Cherenkov Telescope with the worldwide
largest reflector currently in operation. The initially achieved low trigger
threshold of 60 GeV has been further reduced by means of a novel trigger that
allows the telescope to record gamma ray showers down to 25 GeV. The high
trigger rate combined with the 2 GHz signal sampling rate results in large data
volumes that can reach 1 TByte per night for MAGIC-I and even more with the
second MAGIC telescope coming soon into operation. To deal with the large
storage requirements of MAGIC-I and MAGIC-II, we have installed the distributed
file system GFS and a cluster of computers with concurrent access to the same
shared storage units. The system can not only handle a sustained DAQ write rate
above 1.2 kHz for MAGIC-I, but also allows other nodes to perform simultaneous
concurrent access to the data on the shared storage units. Various simultaneous
tasks can be used at any time, in parallel with data taking, including data
compression, taping, on-line analysis, calibration and analysis of the data.
The system is designed to quickly recover after the failure of one node in the
cluster and to be easily extended as more nodes or storage units are required
in the future.
