Reference: Data Access: srm

Last modified: Fri Oct 31 15:29:33 GMT 2008

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For an introduction to GRID data access please see Tutorial: Accessing Storage Elements. For help in selecting the best access protocols see The MINOS UK Data Model Currently MINOS doesn't use srm.

Somewhat confusingly (but perhaps not unexpectedly, this is the GRID after all) I have found:-

Statements that SRM provides management services for the storage resources but precludes file transfer.
Almost every reference I do find to srm commands that interrogate or transfer files, turns out to be an API to access dCache SEs via GRID certified interface. For examples of srmcp, srm-get-metadata, srm-advisory-delete and srm-storage-element-info see D-Cache SRM HOWTO Chapter 11. Using Dcache Client tools
One expert assures me that srm interface that will allow us to list, read and write files. As such it offers the lowest generic interface to the storage technologies we might encounter (CASTOR, dCache and DPM), but ...
... another warns that middle-ware SRM protocols are changing from V1 to V2 and this isn't an area for the non-expert

Despite all of the above, I did manage to copy a file out of dCache on the RAL UI:-

  srmcp -debug=true \
    srm://dcache.gridpp.rl.ac.uk:8443/pnfs/gridpp.rl.ac.uk/data/minos/nwest/test/LVJ_F00034638_0000.mdaq.root \
    file:////tmp/test1.txt

However, on the Oxford UI the same command failed:-

  org.globus.ftp.exception.ServerException: 
    Server refused performing the request. 
      Custom message: Server reported transfer failure (error code1) 
      [Nested exception message:  Custom message: 
      Unexpected reply: 426 Transfer aborted, closing connection 
      :Unexpected Exception : java.net.ConnectException: Connection timed out].  
       Nested exception is org.globus.ftp.exception.UnexpectedReplyCodeException:  
       Custom message: Unexpectedreply: 426 Transfer aborted, closing connection :
       Unexpected Exception : java.net.ConnectException: Connection timed out
        at org.globus.ftp.vanilla.TransferMonitor.run(TransferMonitor.java:178)
        at org.globus.ftp.vanilla.TransferMonitor.start(TransferMonitor.java:105)
        at org.globus.ftp.FTPClient.transferRunSingleThread(FTPClient.java:1451)
        at org.globus.ftp.GridFTPClient.extendedGet(GridFTPClient.java:452)
        at org.globus.ftp.GridFTPClient.extendedGet(GridFTPClient.java:416)
        at org.dcache.srm.util.GridftpClient$TransferThread.run(GridftpClient.java:842)
        at java.lang.Thread.run(Thread.java:534)
        GridftpClient:  transfer exception

so I am not sure how useful it is.

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Reference: Data Access: srm

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