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Duke and ANL ASC Tier 3 (stand alone Tier 3’s) . Doug Benjamin Duke University. ANL ATLAS Analysis Center. “prototype” Tier 3 Used to develop all of the scripts needed to setup a Tier 3 site – Used to test tools and software to train others
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Duke and ANL ASC Tier 3(stand alone Tier 3’s) Doug Benjamin Duke University
ANL ATLAS Analysis Center • “prototype” Tier 3 • Used to develop all of the scripts needed to setup a Tier 3 site – • Used to test tools and software to train others • Expect it to grow as the number of users at the ASC increases • Developing puppet configurations at this site • Supported by DPB (very part time) • Use Xrootd.org Yum repository for most libraries • OSG Yum repository for the gridftp bits
“baseline” Tier 3g public/private networks Standalone xrootd data server Head = redirector Clustered xrootd storage Xrootd data servers all on private network only
Baseline Tier 3 (public/private network) All data access within cluster (LAN) via private network Use case 2. – storage on worker node data servers as part of Federation Physical machine w/ local xrootd functionality Outgoing read only data flow Overlay xrootd functionality Head node xrootd Proxy (public network) Head node -Xrootd read-only redirector(private network) Public IP network Xrootd clustered storage (private network) Stand alone Xrootd data server Head Node/Redirector Xrootd read-only data server(private network) Xrootd read-only data server(private network) Xrootd read-only data server(private network) Private network worker Node/ xrootd data server worker Node/ xrootd data server worker Node/ xrootd data server
Xrootd configuration • Wiki page with example configuration • https://twiki.cern.ch/twiki/bin/view/Atlas/Tier3gXrootdSetup • Know issues • “sss” xrootdfs • Frmchecksuming turned off - Due to configuration of the data servers (oss.localroot).
Duke Tier 3 • Support • Department system admin’s • DPB (very part time) • Puppet helps reduce the loads • Disk heavy worker nodes and on big file server (SL 6) • Stand alone SL 5 gridftp server (used a proxy server) • Use Xrootd.org Yum repository for most libraries • OSG Yum repository for the gridftp bits
Public network version of Baseline Tier 3 Use Case C. - data from all data servers (WN and stand alone) Physical machine w/ local xrootd functionality Information flow to global redirector Outgoing read only data flow Overlay xrootd functionality Outgoing read only data flow Head node -Xrootd read-only redirector Xrootd read-only data server Xrootd clustered storage Stand alone Xrootd data server Head Node/Redirector Xrootd read-only data server Xrootd read-only data server Xrootd read-only data server Public IP network worker Node/ xrootd data server worker Node/ xrootd data server worker Node/ xrootd data server
Xrootd usage at Duke • Users begrudgingly are using Xrootd • More senior folks like to use NFS like access • Then to use xrootdfs to access the storage • Graduate students much more adaptable.