dCache,a Distributed Storage Data Cahing System
MichaelErns;CharlesWaldman;等
【期刊名称】《高能物理与核物理计算国际会议公报：英文版》 【年(卷),期】2001(000)001
【摘要】This article is about a piece of middle ware,allowing to convert a dump tape based Tertiary Storage System into a multi petabyte random access device with thousands of channels.Using typical caching mechanisms,the software optimizes the access to the underlying Storage System and makes better use of possibly expensive drives and robots or allows to integrate cheap and slow devices without introducing unacceptable performance degadation.In addition,using the standard NFS2 protocol,the dCache provides a unique view into the storage repository,hiding the physical location of the file data,cached or tape only.Bulk data transfer is supported through the kerberized FTP protocol and a C-API,providing the posix file access semantics,Dataset staging and disk space management is performed invisibly to the data clients.The project is a DESY,Fermilab joint effort to overcome limitations in the usage of tertiary storage resources common to many HEP labs.The distributed cache nodes may range from high performance SGI machines to commodity CERN Linux-IDE like file server models.Different cache nodes are assumed to have different affinities to particular storage groups or file sets.Affinities may be
dCache,a Distributed Storage Data Cahing System
