Tape logging- SAM perspective

1
Tape logging- SAM perspective

• Doug Benjamin
• (for the CDF Offline data handling group)

2
SAM Data logging
Enstore
Metadata (tapes)
Same machine
Control data
SAM data logging process
Data Stager (Sam - Fss) (CDF specific - fcdfsg1)
Raw Data
Metadata
Control data
SAM Databaser server
Data Logger Disks
File Metadata
Offline database
3
Suggested configuration within Data Logging
machine
One raided Disk Array subsystem
Write here
read here
Write to 1 partition - read from another
rotating through partitions
4
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)