EDG Resource Broker for the Glue Schema Sergio Andreozzi INFN-CNAF Bologna (Italy)

Bologna Feb 18,2003DataTAG WP4 meeting 2 OUTLINE Activity summary – Aug ’02->now Main encountered problems and their solutions Future evolutions

Bologna Feb 18,2003DataTAG WP4 meeting 3 From the beginning to the current status Aug ’02 – first Glue schema LDAP implementation for the CE and draft implementation for the SE Sep ’02 – S.Monforte has started RB porting (version , 1 week) Oct-Nov ’02 – S.Andreozzi, V.Ciaschini, E.Ronchieri finalized a working version for the SC2002 demo Gen ’02 – S.Andreozzi, V.Ciaschini, E.Ronchieri ported the RB, vers _2

Bologna Feb 18,2003DataTAG WP4 meeting 4 Problems and solutions: services and systems separation Glue Schema: separation between service and systems implementing them – > different information types before were in the same entry (CE), now are split in two entries (CE, Subcluster) CE1CE2 Cluster CE1CE2 Sub Cluster Vo name Vo name

Bologna Feb 18,2003DataTAG WP4 meeting 5 Problems and solutions: services and systems separation For each CE – first query for the service – Second query for the system – Merge of results – classAd transformation This does not sensitive affect performances It can be possible to improve it – Possible strategies: query one time the subcluster for all CE’s use of ‘entry keys’ (fictious) to get both CE and subcluster data at once

Bologna Feb 18,2003DataTAG WP4 meeting 6 Problems and solutions: matchmaking when local SE Problem: – Data Access Protocols are published in the SE – Required DAP for a job are specified in the JDL – IF at least one required DAP matches one SE DAP, THEN OK DOES THIS ALWAYS WORK? – NO E.g. – For the SE edt001 file, gridftp and rfio are advertised – The user specifies file as DAP – The broker might match this SE with a CE that does not have local access to the SE

Bologna Feb 18,2003DataTAG WP4 meeting 7 Problems and solutions: matchmaking when local SE Glue Broker strategy: – Data Access Protocols are published in the SE – Required DAP for a job are specified in the JDL – IF (at least one required DAP matches one SE DAP) AND NOT (only DAP file matches on a SE not locally accessible by the CE), THEN OK

Bologna Feb 18,2003DataTAG WP4 meeting 8 Problems and solutions: matchmaking when local SE Ideal strategy: – Each system advertises its Data Access Protocols ( a system can provide Computing or Storage Services) – Each Computing/Storage Service advertises enabled DAP’s – Required DAP for a job are specified in the JDL – IF (at least there is one common required DAP among enabled by an SE, enabled by a CE and required in the JDL, THEN OK This is the most general!!!

Bologna Feb 18,2003DataTAG WP4 meeting 9 Future evolutions With Glue Schema 1.x, for each service the related Information Service URL will be published – Use this info to free the broker from the constraint of ALL GRIS’s on the same port Enable the possibility of specify a minimum amount of disk space for the SE RLS testing OTHER IDEAS???