This section describes relataionship of DBS with other CMS sub-systems.


In General: DBS (Dataset Bookeeping Service) keeps a map of datasets to file blocks/lfn groups. DLS (Dataset Location Service) keeps a map of file blocks to physical locations

RefDB is the old DBS, PubDB is the old DLS. The data from the RefDB will be imported into the new DBS, similarly for PubDB/DLS

ProdAgent: ProdAgent will have its own local scope DBS and DLS that it uses which will be private for that prodAgent. This will be used to produce MC data and when it gets done, it will be promoted to a global DBS/DLS so that users can get to it.

RefDB used to also do MC request /production management, this functionality will move to the ProdMgr, and there will be an MCRequest interface for users to make requests against.

CRAB will use the global DBS/DLS to generate jobs to process a dataset with an analysis job.


All question were addresses and answered by Dave Evans.

How ProdAgent will deal with local DBS/DLS?
There will be a local DBS/DLS per prodAgent that will contain details for all the work being done by that prodAgent There will be one entry in this DBS for every file produced by the prodAgent, these entries will belong to datasets (Eg Generated data , simulated data for a given request) All data for that prodAgent will be catalogged in the local DBS/DLS. After processing jobs are complete, a merging process will reorganise the job output into large files and those files will be Xfered out to the global scope.

How prodagent setup local DBS/DLS?
The ProdAgent has a local MySQL DB. It will include its local DBS and DLS in this DB (At present for testing/development this is not the case, a central DB at cern is used). The prodAgent can be configured to point to any DBS or DLS in principle. by default it will install its own and use that.

How uniqueness is achieved?
The DBS enforces uniqueness in files in it. The ProdMgr/Global request manager will ensure that different prodAgent produce globally unique data within a request. LFN's will be unique in each dataset, DBS will enforce this. Generation of unique LFNs within a dataset will be done by the ProdMgr.

Does ProdAgent interact with CRAB?
ProdAgent doesnt interact with CRAB.

It produces data and publishes it, When the data gets to the global scope, crab jobs can be used to analyse it.

ProdAgent does generation and processing, CRAB does user analysis on a dataset.

How users will generate MC w/ ProdAgent?
There are two potential avenues in the future: Small samples (<10k events) can be done by a user service prodAgent available as a T2 Service Large Samples will be made by filling out a Request web form and putting it into the official system

Neither of these exist yet.

At present all production is "pre-production" and is being handled by developers of teh production system as part of the development and verification exercise. You can use the current prodAgent to generate jobs without DBS DLS stuff, you can just feed in your cfg file and have the prodAgent make and submit the jobs.... bear in mind that this is a pretty bleeding edge thing at the moment....

-- ValentinKuznetsov - 09 May 2006
Topic revision: r1 - 09 May 2006, ValentinKuznetsov
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