Thursday 16 May 2013

CMM's Chemistry X-ray Facility is on Mirage

As of a couple of days ago, the "B2" and "B5" instruments in the CMM's Lab in Chemistry are now connected to Mirage.

So now all 4 CMM Labs are "on Mirage" to some extent.

Technical stuff

The Chem Lab instruments don't save their data directly to a Samba server (like the other Labs).  Instead, they save their data locally, and the data is "pulled" by a periodic rsync from CMMData.  (This used to happen, once a day, but now it happens every 20 minutes.)

This presented a couple of "interesting challenges":
  • The data grabber software needed significant changes to cope with files delivered by rsync.  The files get touched repeatedly by the rsync, so we need to take special steps to prevent them being ingested multiple times.
  • The B5 machine is one of a few machines that are operated by CMM staff exclusively doing runs for CMM users. So we needed to implement a special mechanism for automatically assigning files to the right CMM user.