Post on 21-Jan-2016
INFSO-RI-508833
Enabling Grids for E-sciencE
www.eu-egee.org
The gLite File Transfer Service:Middleware Lessons Learned formService Challenges
Paolo BadinoOn behalf of the JRA1 Data Management team
CHEP06 - Mumbai, 14 February 2006
The gLite File Transfer Service: Middleware Lessons Learned from the Service Challenges 2
Enabling Grids for E-sciencE
INFSO-RI-508833
Outline
• The gLite File Transfer Service – in LCG Service Challenge 3– Architecture– Administration– Security
• Result
• LCG Service Challenge 4
The gLite File Transfer Service: Middleware Lessons Learned from the Service Challenges 3
Enabling Grids for E-sciencE
INFSO-RI-508833
gLite File Transfer Service
• Low Level, point to point data movement service• Part of the gLite Middleware• Asynchronous transfers• Based on Globus GridFTP, SRM• Retry policies
• Not just a Reliable Transfer Service
The gLite File Transfer Service: Middleware Lessons Learned from the Service Challenges 4
Enabling Grids for E-sciencE
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LCG Service Challenges
• Production Quality• Focus on Service:
– Network service– Robust file transfer service– Sustainability
• Heterogeneous Environment– Castor2, dCache, DPM
• Service Challenge 2– Radiant
• Service Challenge 3– FTS (gLite 1.4.1)– CMS Phedex
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The Key Concept: The Channel
• Logical unit of management– Represent a directed network pipe between two sites
• Mono-directional• Independently manageable
– State– Number of streams – Number of concurrent transfers
• Inter-VO scheduling– VO share
• No Routing
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FTS Architecture
• FTS Web Service– User, Administration and Monitoring Interfaces
• File Transfer Queue
• File Transfer Agents– VO Agents– Channels Agents
• SOAP API and CLI
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Transfer Jobs and Files
• Job– Represent the transfer request– Identified by a GUID
• File– source-destination file names pair
Job States File States
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Channel Administration
• Channel has a number of properties– State
Active Inactive Drain Stopped Halted
– Number of concurrent files transfers– Number of streams– VO Share
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Channel Agent Properties
• Transfer Type– SRM Get & Put + 3rd party GridFTP – SRM Copy
• Timeouts– SRM interactions– Transfer– Transfer Markers
• TCP Buffer Size
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Security: Roles
• Submitter User• Administrator• Vetoed User
• Channel Manager• VO Manager
• Gridmap files• VOMS roles
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Security: Delegation
• Delegated User Credentials retrieved from MyProxy
• Agents are Authorized Retrievers– Enough for Production– … problematic for Analysis
• Delegation PortType
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Monitoring
• Provides statistic information based on the FTS behavior and usage– Snapshots of number of requests in a given state– Average rate and bytes written in a given period
• Grouped by VO or Channels
• Channel Monitoring
The gLite File Transfer Service: Middleware Lessons Learned from the Service Challenges 13
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INFSO-RI-508833
FTS Web Interface
The gLite File Transfer Service: Middleware Lessons Learned from the Service Challenges 14
Enabling Grids for E-sciencE
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Retry Logic
• Simple retry strategy– Retry all the files up to 3 times, independently of the error reason
• Complex retry strategy (gLite 1.5)– Evaluate the transfer attempts history – Resilient to failures in the error handling
• Experiments’ specific retry logic (gLite 1.5)
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What SC achieved so far
• SC3 Rerun (January 2006)• All sites achieved target rate• 8/11 sites achieved nominal rate
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Preparing for SC4
• Stability• Sustainability• Robustness
• Monitoring• Procedures• SRM v2• Integration with experiments’ frameworks
– Hooks/Catalog plug-ins
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Summary
• gLite FTS – Reliable Transfer Service– Transfer Management Tool
• LCG Service Challenge 3– Architecture
Channels
– Security– Feedbacks from experiments– Results achieved
• FTS in LCG Service Challenge 4
The gLite File Transfer Service: Middleware Lessons Learned from the Service Challenges 18
Enabling Grids for E-sciencE
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Links
• gLite– http://www.glite.org/
• gLite JRA1 Data Management– http://egee-jra1-dm.web.cern.ch/egee-jra1-dm/
• Service Challenges Wiki– https://twiki.cern.ch/twiki/bin/view/LCG/LCGServiceChallenges
• FTS Wiki– https://twiki.cern.ch/twiki/bin/view/EGEE/FTS/