LHC Computing Grid Deployment Schedule 2006-08

 CERN-LCG-PEB-2005-05  -  version 2 - 18 April 2005 (lr)
   update history

 

 

 

 

Data Recording

CERN must be capable of accepting data from the experiment data acquisition (DAQ) systems and recording it on magnetic tape at a long term sustained average rate of 1.6 GBytes/sec during the proton run and 1.85 GBytes/sec during the ions run. During 2004 the disk-tape writing rate was demonstrated at 1 GByte/sec. In March 2005 the recording rate for simulated DAQ through mass storage system to tape was demonstrated at 450 MBytes/sec. The target DAQ-mass-storage-tape rate achievable at the end of December 2005 is 750 MBytes/sec, rising to the full nominal data rate of 1.6 GBytes/sec by August 2006. These demonstrations must be performed in parallel with the Service Challenge activities described below.

 

Service Challenge 2

The goal of Service Challenge 2 is to demonstrate reliable file transfer, disk to disk, between CERN and at least 5 Tier-1 centres, sustaining for one week an aggregate throughput of 500 MBytes/sec at CERN.  The minimum capability at each Tier-1 is 100 MBytes/sec. The Tier-1 sites taking part are BNL, CNAF, FNAL, GridKA, IN2P3, NIKHEF/SARA and RAL.

The service should use the initial version of the reliable file transfer service, provided by CERN.

The target is to complete this challenge by end April 2005.

 

Service Challenge 3

Service Challenge 3 operates a reliable base service including most of the Tier-1 centres and some Tier-2s. It has two phases – a setup phase terminating with a throughput test, followed by a three-month period of stable operation during which experiments may carry out tests of their software chains and computing models.

The throughput goals at each Tier-1 are 150 MBytes/sec network-disk, and 60 MBytes/sec network-tape, with CERN capable of supporting 1 GByte/sec disk-network.

The goal of the throughput test is to maintain for one week an average throughput of 400 MBytes/sec from disk at CERN to tape at the Tier-1 sites.  The Tier-1 sites taking part are ASCC, BNL, CNAF, FNAL, GridKA, IN2P3, NIKHEF/SARA, RAL and Triumf. The target date for completing the throughout test is end July 2005.

The service phase of Service Challenge 3 will include additional software components, including a grid workload management system, grid catalog, mass storage management services and Virtual Organisation (VO) management services. A small number of Tier-2 sites will also be involved, each supported by a Tier-1 centre. The initial list of participating Tier-2 centres and their supporting Tier-1s is given in the table below. The service phase is scheduled to operate for three months from September to December 2005.

 

Tier-2 / Federation

Tier1

Experiment

Bari, Italy

CNAF, Italy

CMS

Turin, Italy

CNAF, Italy

Alice

DESY, Germany

GridKA, Germany

ATLAS, CMS

Lancaster, UK

RAL, UK

ATLAS

London, UK

RAL, UK

CMS

ScotGrid, UK

RAL, UK

LHCb

US Tier2s

BNL / FNAL

ATLAS / CMS

Table 1: Core Set of Tier-2 Centres in Service Challenge 3

 

Service Challenge 4

Service Challenge 4 aims to demonstrate that all of the offline data processing requirements expressed in the experiments’ Computing Models, from raw data taking through to analysis, can be handled by the Grid at the full nominal data rate of the LHC. All Tier1 sites will be involved, together with the majority of the Tier2s. The challenge must complete at least 6 months prior to first data taking, when it will become the production service for LHC and is made available to the experiments for final testing, commissioning and processing of cosmic ray data.

The setup phase ends with a throughput demonstration sustaining for three weeks the target data rates at each site as defined in the following table. The throughput is measured network-tape at each Tier-1, and disk-network at CERN. The target date for completing the throughput test is end April 2006.

 

Centre

ALICE

ATLAS

CMS

LHCb

Target Data Rate MBytes/sec

ASCC

 

X

X

 

110

CNAF

X

X

X

X

220

PIC

 

X

X

X

200

CC-IN2P3

X

X

X

X

220

GridKA

X

X

X

X

220

RAL

X

X

X

X

220

BNL

 

X

 

 

65

FNAL

 

 

X

 

50

TRIUMF

 

X

 

 

65

NIKHEF/SARA

X

X

 

X

175

NORDIC DATA GRID FACILITY

X

X

 

 

90

Target data rate at CERN

1,600

Table 2 – Nominal Network/Tape Data Rates by Site

 

The service phase of Service Challenge 4 will include the basic software components required for the initial LHC data processing service, as defined in the LCG Technical Design Report. The service must be able to support the full computing model of each experiment, including simulation and end-user batch analysis at Tier-2 centres. The service phase is scheduled to operate for four months from May to September 2006.

 

Initial LHC Service

The initial LHC service is scheduled to enter operation by end September 2006, capable of handling the full nominal data rate (see Table 2). The service will be used for extended testing of the computing systems of the four experiments, for simulation and for processing of cosmic data. During the following six months each site will build up to the full throughput needed for LHC operation, twice the nominal data rate.