Dynamic Megatable

Preliminary conclusions

General

• The goal is to publish information in the information system that could be useful for providing the management with a view of the installed capacity and resource usage by the VOs at sites. This info can also be used by VO operations people in order to "monitor" their usage of the resources
• It was decided to use the GlueSA class to publish the needed information
• Only online resources are published for the moment, although information providers developers should investigate if there is a way to publish as well tape usage information.
• In particular, the GlueSAReservedOnlineSize should be used to publish the SA online size reserved [to a VO] (it is not clear if this information can be dynamic since we cannot rely on the site admin changing this info manually). This is really what has been allocated and installed. The GlueSATotalOnlineSize is the total at a given time (whatever is visible, not counting broken disk servers, draining ones, etc.). Each information provider developer should comment on what it is assumed to be GlueSAUsedOnlineSize.
• For an agreed definition of Used and Free space, please check the Storage Element Model for SRM 2.2 and Glue schema description document
• Shared [among VOs] space will be grouped together in one [or more SAs] which publish multiple GlueSAAccessControlBaseRule entries.
• Action: Flavia will check with the client providers (FTS, lcg-utils,gfal, SAM, etc.) that none of the above will break the current client assumptions.
• Legacy clients are not concerned by the changes, since for them the old GlueSA object is anyway published (and will be published by the new information providers).

CASTOR

• Action: Jens will send around a description of the current dynamic information providers with details about the fields provided by June 16th.
• Action: Jan will install the dynamic info at CERN on a test instance to make sure they are complete and make sense (date to be determined)
• Action: Flavia will run the S2 test suite on the provided information to make sure they are compliant.

dCache

• For dCache read or "special" pool the GlueSACapability entries will be used to distinguish among available disk pools
• Action: Ron Trompert will provide a draft description of the GlueSA entries as interpreted for dCache by June 16th.
• Action: Ron Trompert will investigate how much time will be needed to change the current information providers to make them conform to this proposal and notify this group.
• Action: Paul Millar will do the equivalent work for the official dCache information providers and notify this group

DPM

• Action: Michel Jouvin will provide a draft description of the GlueSA entries as interpreted for DPM by June 16th
• Action: Michel Jouvin will investigate how much time will be needed to change the current information providers to make them conform to this proposal and notify this group.

Other actions

• Action: Flavia will come up with a high level view of the proposal for the MB on June 17th and circulate it to this group
• Action: Flavia will start a technical document collecting the descriptions received by the people in this group.

-- FlaviaDonno - 16 Jun 2008