Associating Users to Tier2's in CMS

What this is

In CMS Computing Model it is assumed that each user has a home disk area at their home Tier2 This will be mapped to in CMS Logical File Name space as /store/user/ This disk area is meant for the following usages:

• destination for remote stage out of ouput from Crab jobs
• local disk space to be used for processing on a local computing facilities data not described in CMS DBS

Ideally this home disk is provided to the user at what we call "their home T2" and CMS recommends of ther order of 4TB per user there. Of course any Tier3 will also do, since the only difference between T3 and T2 is that T3 does not pledge resources to global CMS computing but only cater to the needs of some local community.

How is it done

The procedure to associate each user to a Tier2 is the following

1. each country with at least one Tier2 site will take care of their users, distributing them across their Tier2's and Teir3's
2. CERN Tier2 is special and cares for CERN residents regardless of nationality
3. countries w/o a T2 can use a local T3 (any SRM will do)
4. countries with no T2 and no usable SRM and a problem in accomodating their users should contact Computing Management via their country representative, so that an ad-hoc solution can be found case-by-case

What do I do as a User

Users should contact their country representative (possibly via their local institution contacts) to know which of the above applies and have the disk space assigned via the proper channels.

-- StefanoBelforte - 30-May-2012