There are two high performance xrootd spaces - The Tier 2 space and the Tier 3 space. These space are primarily for storing ROOT files and ATLAS datasets. Creating a new file or directory on a Xrootd space takes at least 5 seconds. So they are not good for large number of small files such as logs, codes, and small text files.
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Tier 3 space
SLAC ATLAS group owns a proof private cluster. It is actually a proof cluster, a batch cluster and a xrootd storage cluster (the Tier 3 space). It was also a proof cluster but the proof function is obsolete.
- On atlint0[1-4] the xrootd storage cluster is mounted at /atlas .
- You can use R2D2 to transfer official ATLAS datasets to the space under directory /atlas/dq2. The Tier 3's name in R2D2 is SLAC-ATLAS-T3_GRIDFTP.
Files under /atlas/proof and /atlas/output are used by the proof jobs.- Space under /atlas/local are for users to read and write.
- In your batch jobs, you can access them via the xrootd protocol (explained below). The accessing URL is root://atlprf01:11094//atlas/...
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filelist = []
filelist += ["root://atl-xrdr//atlas/rucio/data15_13TeV:DAOD_MUON0.06783725._000004.pool.root.1"]
filelist += ["root://atl-xrdr//atlas/rucio/data15_13TeV:DAOD_MUON0.06783725._000001.pool.root.1"]
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athenaCommonFlags.PoolESDInput=filelist |
Experimental: If the files are not at SLAC but are available in an ATLAS site that provides xrootd service, you can also access them by replacing "atl-xrdr" by "atlfax" (see below).
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filelist = []
filelist += ["root://atlfax//atlas/rucio/data15_13TeV:DAOD_MUON0.06783725._000004.pool.root.1"]
filelist += ["root://atlfax//atlas/rucio/data15_13TeV:DAOD_MUON0.06783725._000001.pool.root.1"]
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athenaCommonFlags.PoolESDInput=filelist |
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