22 March 2009

WLCG workshop part I

Lots of presentations and talks at the WLCG workshop. As usual much of the work is done in the coffee breaks.
From the storage perspective, there was talk about "SRM changes" which was news to me (experiments require (a) stability, and (b) change, you see). Upon closer investigation, it turns out to be about implementing the rest of the SRM MoU. One outstanding question is how these changes are implemented without impacting users (in a bad way).
Fair bit of talk about xrootd support. xrootd is considered a Good Thing(tm), but the DPM implementation is rather old (2 years). It is possible it can benefit from the new CASTOR implementation for 2.1.8.
Some talk about SRM performance. The dCache folks as usual have good suggestions, Gerd from NDGF suggests using SSL instead of GSI. I believe srmPrepareToGet should be synchronous when files are on disk, this should lead to a large performance increase. Talking to other data management people, we believe the clients should do the Right Thing(tm), so no changes required. Of course the server should be free to treat any request asynchronously if it feels it needs to do this, eg to manage load.
Talked to Brian Bockelman from U Nebraska; they have good experiences with (recent versions of) Hadoop, using BeStMan as the SRM interface.
More later...

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