22 January 2007

Finally I get round to posting something about last weeks dCache workshop at DESY.

The workshop was a ~2 day affair. The first half of day 1 was devoted to Tier-1/2 site reports. Clearly there is a lot of good work getting done within the community and it was useful to see how the Tier-1s are configuring their dCache systems. A couple of things could be noted.

1. The Tier-1s are improving the performance of their systems by splitting the dCache admin node services across multiple machines. Typically the SRM, postgres and PNFS servers were being given dedicated machines. The talk on the second day by Martin Gasthuber gave further recommendations on hardware configuration.

2. Both FNAL and IN2P3 have developed their own set of tools for monitoring dCache activity. The lack of good dCache monitoring tools proved to be a common theme when talking to people at the workshop. The new SRMWatcher functionality that Timur Perelmutov (SRM developer) should help in this respect. Unfortunately they were again recommending that if you ran this process along with the SRM then a separate node should be used (due to the potential load that users could place on the database).

There was also a presentation from Sun about their new storage solution, the
Sun Thumper (X4500) and their new filesystem ZFS. The presentation given by two of the ZFS developers was very interesting, if a little too well rehearsed. ZFS does look powerful though, being able to pool disk resources (in a similar way to dCache/DPM), taking instant snapshots of the filesystem, copy-on-write...

The second half of the day was taken up with presentations about the status of the dCache SRM v2.2 implementation. This was all good stuff and it looks like the final version will be out at the start of April in dCache v1.8.0. There was a short presentation about the dCache xrootd door and how they plan to implement GSI security with it. The gPlazma functionality of dCache was also presented. Present from v1.7.0 onwards this allows dCache to deal with the concept of VOMs roles which will eventually replace the gridmap-file (dcache.kpwd) although gPlazma (being Pluggable) does support this mechanism by default.

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