Tape logging- SAM perspective Doug Benjamin (for the CDF Offline data handling group)

Data Logger Disks Enstore SAM Data logging Raw Data Control data File Metadata Data Stager (Sam - Fss) (CDF specific - fcdfsg1) SAM Databaser server Offline database SAM data logging process Control data Metadata (tapes) Metadata Same machine

Suggested configuration within Data Logging machine Partition A Partition B Partition X …. Write here read here Write to 1 partition - read from another: rotating through partitions One raided Disk Array subsystem

Available Hardware and Tests to do (in FCC) One AtaBeast disk subsystem w/ 2 raid controllers ( ~ 14 TB) 1 - dual processor front end head node (fcdfdata155 2 XEON, 3.2 Ghz) Can ask for another head node. Tests (includes SAM metadata declaration etc) - Write to one partition and read from another (measure the rates) Go through all partitions in this manner Write 1 GB files to Null movers to measure write to tape system Write to tape (1-2 day test) to measure sustained rate Need people to do the tests and write the code (offline DH will help but we are overloaded)