1 Meeting Location: LBNL Sept 18, 2003 The functionality of a Replica Registration Service Attendees Michael Haddox-Schatz, JLAB Ann Chervenak, USC/ISI Jean-Philippe Baud, CERN Timur Perelmutov, Fermi Don Petravick, Fermi Doug Olson, LBNL Alex Sim, LBNL Arie Shoshani, LBNL

2 Generalized Replica Management Service Replicate {LFN}  siteReplicate {LFN}  site Lookup LFNs – find out which RLS to use Planning: select PFNs / SURLs for accessing files Allocate space Move files robustly Register files

3 Simple Replica Management: focus on three services Dynamic Space AllocationDynamic Space Allocation Now space is pre-allocated Future: request space reservation Multi-file replicationMulti-file replication Managing the entire multi-file request Use file transfer services Guarantee robustness Replica RegistrationReplica Registration Into one or more catalogs Can register into standard Replica Catalogs Can register into specialized experiment file catalogs

4 Replica Management Architecture Replica Management Service Multi-file Replication Service Replica Registration Service Client File Transfer Services Replica/File catalog Services

5 Replica Management for STAR Experiment Replica Management Service Replica Registration Service Client GridFTP (bbftp) STAR File Catalog DataMover HRM

6 Replica Management for STAR Experiment Replica Registration Service Client GridFTP (bbftp) STAR File Catalog DataMover HRM

7 Generalizing the Concept: Need to Standardize APIs Replica Management Service Multi-file Replication Service Replica Registration Service (RRS) Client File Transfer Services Replica/File catalog Services Multi-file Replication Service Multi-file Replication Service (MRS) SRMs Magda SRB … File Transfer Services File Transfer Services GridFTP bbftp scp … Replica/File catalog Services Replica/File catalog Services RLS MCAT STAR-FC ATLAS-FC … Multi-file Replication specReplica Registration spec Replica Registration APIMulti-file Replication API

8 Three use cases Client generated a bunch of filesClient generated a bunch of files Call a RepReg service to register to one or more RepCats Client want to replicate a bunch of files (or directory)Client want to replicate a bunch of files (or directory) Call RepReg with different modes Want to delete one or more filesWant to delete one or more files Should a RepReg service to cleanup catalogs? Question: how the RepCats chosen?Question: how the RepCats chosen? We propose to use the MDS for that Qusetion: should RRS be a separate (external) serviceQusetion: should RRS be a separate (external) service Yes, because it is too much to impose on underlying RepCats Yes, because it is a common functionality to all RepCats Yes, because it has value as a separate service

9 Replica Management Architecture Replica Management Service Multi-file Replication Service Replica Registration Service Client File Transfer Services Replica/File catalog Services Monitoring & Discovery Service Default RepCats Find RepCats (optional)

10 Functionality of Replica Registration Registration modesRegistration modes File-at-a-time registration Mode 1: register all the files that were replicated successfully, and report which failed. Mode 2: stop registration process if there is a failure in registration, report which failed. Global registration: after the entire multi-file replication finished Mode 3: register only if all file replications are successful. Mode 4: register all files that were successfully replicated, and report which failed, if any. Failures are in terms of registering to a RepCat E.g. RepCat database is full or down Assume – immutable files, LFN-PFN duplication is error Register to any catalogsRegister to any catalogs Standard catalogs – e.g. RLS Specialized catalogs – e.g. experiments file catalogs Issue: need a standard for RepCat interface In the meantime we need have a plug-in type service

11 Functionality of Replica Registration (Cont’d) Queue registration requestsQueue registration requests Request token Multi-file reg capability Permit multiple registration modes File-a-time (as quickly as you can): mode 1 or mode 2 Bulk (do it all or do none => roll back): mode 3 or mode 4 Failure: no-response, no space, file-already-registered Permission – security: GSI proxy + user name for now Access control – specify r/w for catalog (limited today, ACLs later) Abort and Roll back registration Commit registration Global reg request (commit implied) RobustnessRobustness Recover from transient failures Retry per request – with time limit (in seconds)

12 Functionality of Replica Registration (Cont’d) Register to multiple catalogs simultaneouslyRegister to multiple catalogs simultaneously Ability to specify which catalogs to register to Refer to RepCats by URLs Manage multiple registration requests for multiple clientsManage multiple registration requests for multiple clients Implementation dependent

13 Functionality of Replica Registration (Cont’d) Asynchronous serviceAsynchronous service Provide dynamic status on registration Success, failed, pending – per file per RepCat Failed: already-in-catalog, ill-formed (keep RepCat error string), not-authorized RepCat not responding – per RepCat RepCat database full – per RepCat Waiting for commit – per request Request timed-out – per request Full Success / partial success (but completed) – per request Provide statistics and failure information Summary per request (History activity information)

14 Un-register Problem: want to delete a file and un-register it from all RepCats that know about it.Problem: want to delete a file and un-register it from all RepCats that know about it. 1) Need to find out where file is registered or 2) broadcast to all RepCat in the VO Prefer 2) because we avoid keeping a state of where files are registered Who issues the notification to un-register a file?Who issues the notification to un-register a file? SRMs – need to have permission Maybe RepCats should check with SRM before removal Should this be a service of RRS?Should this be a service of RRS? Probably, but not in first version