Monday, August 25, 2008

Glasgow on the move

Because of the current problems at RAL, Glasgow was nominated as a test peripatetic Tier-2, so see how agile ATLAS production was at moving Tier-2 resources in case of T1 downtime (note this test only works if the cloud services, FTS and LFC, are still running - if these are gone then it's almost impossible, today, to use any of the cloud's Tier-2s).

First off Glasgow was sent South East, into the NL cloud. Here we found a problem with the input datasets, because input datasets to T2s (which are subscribed without sources) only look for sources within the cloud (this follows the ATLAS computing model). However, the way around this is to specify the associated T1 (for production) as the source and then DQ2 does the work. The panda developers made the change on Friday, so that NIKHEF was specified as the source for inputs to Glasgow. Likewise, for output back to the NL T1, Glasgow's PRODDISK token was specified explicity as the source.

That done, Glasgow galloped through a couple of hundred jobs for the NL cloud, before they ran out of jobs:

Flushed with this success we've just shoved Glasgow into the FR cloud for a while, as they still have jobs left to run. Within an hour we're running a couple of 100 jobs.

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