Data Storage and Handling at FermilabEnstore Enstore Online Monitoring | Documentation Enstore is the mass storage system implemented at Fermilab as the primary data store for experiments' large data sets. It provides distributed access to data on tape or other storage media both local to a user's machine and over networks. Enstore is designed to provide high fault tolerance and availability sufficient for the RunII data acquisition needs, as well as easy administration and monitoring. It uses a client-server architecture which provides a generic interface for users and allows for hardware and software components that can be replaced and/or expanded.
Enstore can be used independenlty or in combination with caching systems such as dCache data bufferring and caching system or SAM data handling system. When
used with caching/buffering system files get written to disks and then
migrate to enstore tapes. For read requests If requested files are not
in the cache they first gets staged from enstore. Caching systems
communicate with Enstore via a high-speed ethernet connection. Using
file caching and buffering allows to decouple the (potentially slow)
network transfer from the (fast) storage media I/O in order to keep the
Enstore system from bogging down. Data exchanges between caching
systems and Enstore are performed automatically and invisibly to the
user.
DiskCache (known as dCache)www.dcache.org | dCache at DESY and FNAL | dCache as used with Enstore The dCache project is a joint DESY-Fermilab effort to overcome the accessibility limitations posed by the types of mass storage software and devices found at HEP labs. The dCache software provides an intermediate layer between the client applications (e.g., the SAM data handling system or a user's analysis program) and the mass storage system (e.g., Enstore). It acts as an intelligent manager between the different layers. The dCache optimizes the location of staged copies and makes better use of possibly expensive drives and robots. It allows integration of slow devices without introducing unacceptable performance degradation. In addition, the dCache provides a unique view into the storage repository, hiding the physical location of the file data (cached or tape-only).
OCS (Operator Communications Software)
OCS (Operator Communications Software) is a package that performs and manages tape drive allocations, operator-assisted tape mounts and tape drive use statistics. Its logical-to-physical tape device name translation helps not only human communication, but hides many platform-specific idiosyncrasies from users.
Send comments about this page via the suggestion form Last updated by cdweb on 03/18/2009 |
OCS is deprecated software, still in use by some experiments at the lab, but used only by legacy systems. 
