Network needs for Analysis (from a talk to INFN in Bologna January 19, 1999)
3 Scenarios (extremes and middle way):
- copy all PADs in Italy, need almost no net to US
- leave all PADs & “ntuple” in US, use Xterm from Italy
- copy some PADs here, keep most Ntuples here (copy/create)
Difficult to estimate requirements. Better the other way around. Given 4 Mbit/sec dedicated to CDF, what can we do ?
- 4 Mb/sec = 200GByte/week = 2 tapes/week, can’t beat DHL !
- 1 tape a day = 100GByte/day = 10 Mbit/sec
- PADs don’t travel on the net
- 4Mb/sec / 10 users = 1GByte/5hr/person for copying Ntuples
- one analysis = 1/10th data ? PAD=20TB, Ntuple=20GB ? refreshing Ntuple takes 4 days min ! More data, more users..
- Converging argument: 10GB ntuple/physicist = minimum !
- Can’t make Ntuple offsite and copy locally on the net