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Learn how to install dCache into an existing storage environment at GridKa, including hardware resources, Tivoli Storage Manager integration, dCache components, access protocols, and tuning for TSM integration.
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Installing dCache into an existing Storage environment at GridKa Forschungszentrum Karlsruhe GmbH Institute for Scientific Computing P.O. Box 3640 D-76021 Karlsruhe, Germany Dr. Doris Ressmann Doris.Ressmann@iwr.fzk.de http://www.gridka.de
ForschungszentrumKarlsruhe Grid Computing Centre Karlsruhe GridKa
780 CPUs 160 TB disk 300 TB tape GridKa planned hardware resources 4000 CPU Disk 3000 Tape kSI95 2000 1000 0
Tivoli Storage Manager (TSM) • TSM library management • TSM is not developed for archive • Interruption of TSM archive • No control what has been archived • dCache (DESY, FNAL) • creates a separate session for every file • Transparent access • Allows transparent maintenance at TSM
compute nodes mountpoint gridftp TSM with tapes dCache main components gridftp srmcp head node file transfer file transfer pools file transfer
PNFSPerfectly Normal File System pool and tape pnfs real data database for filenames metadata 0000000000000000000014F0 000000000000000000001510 0000000000000000000015A0 0000000000000000000017E8 000000000000000000001858
dCache interface • dCache Access Protocol (dcap) • compute node: dccp <source file> <pnfs mountpoint> • connection to head node • return available pool node • copy direct into available pool node • dc_open(...); • dc_read(...); • pool: data is precious (can't be deleted) • flush into tsm • data is cached (can be deleted from pool) • compute node: dccp <pnfs mountpoint> <destination file> • if not in pool the data will be taken from tsm
Test EnvironmentProblematic Hardware • RAID controller 3WARE with 1.6 TB • Always Degraded mode • Rebuilding • 70 kB/s or 10 MB/s • Lost data
TSM properties • TSM disk cache overflow • Allocation of tape drives (max 2) • Adapt server properties for specific dCache requirements • Management Class (retention time) • Copy groups
Conclusion and Future Work • More reliable hardware especially for write pools • Several TSM server • SRM and LCG connection • Pools on parallel File system GPFS