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SLAC Tier 3 Status. Wei Yang Federated Xrootd Workshop University of Chicago Sept 12-13, 2011. Hardware. Storage / Proof Farm Dell R510, 2.4Ghz 8x cores, 24GB, 1Gb 1 head node: 2x 2TB 7200rpm SATA 7 work nodes: each 12x 2TB 7200rpm SATA Access WT2 stoage via Xrootd
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SLAC Tier 3 Status Wei Yang Federated Xrootd Workshop University of Chicago Sept 12-13, 2011
Hardware • Storage / Proof Farm • Dell R510, 2.4Ghz 8x cores, 24GB, 1Gb • 1 head node: 2x 2TB 7200rpm SATA • 7 work nodes: each 12x 2TB 7200rpm SATA • Access WT2 stoage via Xrootd • Accessible via WT2’s SRM/GridFTP • 2x RHEL5 interactive machines • Mount Tier 2 and Tier 3 storage via XrootdFS • Also run Proof Lite • 2x SUN v20z (1.7Ghz 2x cores, 2GB, 1Gb) • Xrootd Proxy cluster, will reduce to 1 host • Development machines, need to find permanent replacement.
Services • Xrootd Storage • 115 TB usable (RAID 6) • Dedicated set of xrootd/cmsd for data serving • Accessible via XrootdFS on interactive machines • Directory structure, follows the standard Tier 3 storage convention for Xrootd /atlas/{dq2, group, local, proof, test} • Will run FRM (tested at testbed)
Services, cont’d • Proof service • Standard alone xproofd daemon with multiple root version supported • A pair of xrootd/cmsd to serve the need of xproofd • May merge the two xrootd/cmsd pairs • if possible and all things are stable • Still trying to navigate through all constrains to make proof work with FAX
User activities • dq2-get from interactive machines • These machines mount T2/T3 storage via XrootdFS • Will be “dq2-get –xprep” • So far haven’t experience the pain of deletion • Run Proof jobs from interactive machines • Recently able to finish large scale jobs • Users are still gaining experience on Proof (and Proof isn’t prefect) • Issues not quite understand: work in progress
Issues with Proof and FAX • Start Proof from Xrootd: • Run as root with –R, no permission issues • Unstable • Doesn’t work with FRM due to ownership issues • Run Proof as a standalone root process (xproofd) • Stable • Xrootd run as non-root • can’t remove temporary files from sandbox • work with FRM • ROOT team working on running Proof as non-root. No timeline is given