Getting data from the FNAL central mass storage system¶
Data from experiments is archived on tape in the FNAL mass store. The tape robot uses a product called ENSTORE to manage the data and retrieve it from tape. There is a disk cache (DCache) sitting in front of the tape robot that files can be staged into. They remain in the cache for some period of time meaning that other users can access the file from disk rather than needing to stage it from tape.
Useful monitoring is available at the STKen Enstore web page.
To report problems with the system please contact the FNAL helpdesk either by phoning 630-840-2345 or filling out the Service Now web form. To ensure that your request gets routed to the correct person please include the words stken enstore or stken dcache in your request and please give as complete a description of the problem as possible. For example if you get an error message please include it.
To find out what runs have been taken use the SAM Database search interface.
This will show you all the data files cataloged in SAM. The search also returns the path to the file.
For Minos, this database contains all the raw data and reco data but not Caldet. Also the Monte Carlo data is not catalogued in SAM yet but it will be added soon. If you are running jobs with multiple files on the <experiment> cluster or the FNALU batch nodes you are encouraged to define a SAM dataset. See the SAM User's Guide for more details.
Raw data can be found at:
with the directory structure underneath the experiment name designed and implemented by each experiment.
For example, minos has: /pnfs/minos/fardet_data for far detector raw data organized by the month in which the data were taken. /pnfs/minos/neardet_data for near detector raw data and so on.
Using the Disk Cache command line interface¶
This requires installation of the dcap package. You can find the tar file and installation instructions on the external packages installation page for minos at: http://www-numi.fnal.gov/offline_software/srt_public_context/WebDocs/external_products.html
This uses a URL syntax to specify the files to fetch. You will need to know the dcache path for the file. The SAM Database search interface will provide this information, select the option to produce dccp style output. For example to copy the raw data file in Minos for run 11732 you type
setup dcap -q unsecured dccp dcap://fndca1.fnal.gov:24125/pnfs/fnal.gov/usr/minos/fardet_data/2003-01/F00011732_0000.mdaq.root F00011732_0000.mdaq.root localfile
This service is accessible off-site but will not work if your site has a firewall in place.
dccp is not a recommended method for off-site access.
Using the Disk Cache with ROOT¶
This requires installation of the dcap package and building a TDCacheFile plugin for ROOT. You can find the tar file and installation instructions on the external packages installation page for Minos at: http://www-numi.fnal.gov/offline_software/srt_public_context/WebDocs/external_products.html
You can then access files from the DCache directly from a ROOT prompt.
Using the Disk Cache FTP interface¶
The data is also accessible from any machine through the Disk Cache ftp interface. This interface provides read-only access using the usual ftp commands. Please note that issuing the ls command in the ftp client is a resource intensive operation because of the database lookups. Please do not do this. Either use the SAM Database search interface to find the location of the files that you want to copy or install the SAM Web Services which allows you to run SAM commands remotely and copy the files to your local host.