dCache tape instance

Data in dCache is organized in a directory tree with given layout. The dCache-tape-instance currently provides two 'toplevel' entry points for archiving data, petra3 and FS. The tape instance pertra3 is foreseen as tape storage of user data taken at PETRA III beamlines and fs provides tape storage for data taken by FS-staff / In-house.

The petra3 instance provides subdirectories labeled by beamline name for most PETRA III beamlines. Those directories are each divided by subdirectories labeled by date. The date-directories are deduced from the year plus an extension 'A' or 'B' and define the last level of the directory hierarchy. The extension 'A' represents beamtimes beginning in the period from 1. January to 31. July, the latter one corresponds to beamtimes beginning in between 1. August and 31. December. Those date-directories contain the archives created by the data migration tool. A schematic layout looks like this:

.1 .../petra3/archive/. .2 p01. .3 2011B. .3 2012A. .3 2012B. .4 archive1.tar. .4 archive2.tar. .4 archive3.tar. .2 p02.1 .2 p02.2 .2 p03. .2 p04. .2 p05. .2 p06. .2 p07. .2 p07b. .2 p08. .2 p09. .2 p10. .2 p11.

The FS instance is organized in a different manner due to manifold data origins and its resulting implications. The FS instance provides subdirectories by year which contain subdirectories named according to the datasets beamtime application ID. This is usually the location in dCache for datasets taken by DESY staff at external facilities (i.e. such beamtime application IDs have been created by FS-EC and are named by '5000NNNN'). In addition, the FS/archive instance also contains a folder which holds data taken at DORIS III.

.1 .../FS/archive/. .2 2003. .2 2006. .2 2008. .2 2009. .2 2010. .2 2011. .2 2012. .2 2013. .3 50000051. .2 doris. .3 2006. .3 2009. .3 2010. .3 2011. .3 2012. .4 10007146. .5 archive1.tar. .2 ....