[Jlab-scicomp-briefs] Filesystem changes: new volatile area; expiring cache DSTs

[Sandy Philpott]

With the purchase of the latest disk storage systems for the 
experimental physics data analysis environment, two filesystem changes 
are being made:  a new /volatile filesystem is available, and 
expirations are being applied to /cache DST assignments.

/volatile is a new high performance, distributed filesystem available 
using Lustre over Infiniband; all systems in the farm were upgraded to 
support Lustre and IB over the summer. The first areas are ready for use 
in /volatile/clas/<rungroup>, to replace the 30TB automanaged 
/work/clas/disk[1-10] areas. In Lustre, these areas will still be 
guaranteed a total of 30TB, but can use up to 80TB if the space is 
available.  The /work/clas/disk[1-10] area will shrink to 0 as the new 
areas grow.  See the new web page at 
http://scicomp.jlab.org/disk/volatile.faces for more information and 
automanagement details. 

For DST cache areas ( http://scicomp/scicomp/jasmine-family-summary.jsp 
), an expiration will be applied so that oldest files are automatically 
removed.  Currently the only way to remove DST cache files is with an 
explicit jcache -d, leaving old data disk resident.   Recall that cache, 
by definition, has a master copy on tape so can be retrieved at a later 
date when needed.

Questions or comments can be directed to your hall's computing 
coordinator, or to philpott at jlab.org.