Hi, back to this issue with solution:
On Sun, Jan 9, 2011 at 12:25 PM, Markus Neteler <[email protected]> wrote: > Hi, > > I am using 6.4 on a cluster to process maps in parallel. > Each job runs as batch job in its own mapset. The jobs > are launched via 'qsub' of Grid Engine which > sends it from the frontend to the various blades of > the cluster. The grassdata directory is shared via > NFS on all blades, the filesystem is XFS. > > Unfortunately, with fast tasks within the batch job, > various mysterious errors randomly occur: > > ... > ./launch_SGE_grassjob_MODIS_filt2.sh.e255664:ERROR: > /usr/local/grass-6.4.1svn/etc/lock: > ./launch_SGE_grassjob_MODIS_filt2.sh.e254776:ERROR: > /usr/local/grass-6.4.1svn/etc/lock: > ./launch_SGE_grassjob_MODIS_filt2.sh.e256639:ERROR: G_getenv(): > Variable LOCATION_NAME not set > ./launch_SGE_grassjob_MODIS_filt2.sh.e257016:ERROR: Unable to make > mapset element .tmp/blade08 > ./launch_SGE_grassjob_MODIS_filt2.sh.e255264:ERROR: MAPSET > terra_lst1km20010420.LST_Night_1km.filt.255184 not found ... > ./launch_SGE_grassjob_MODIS_filt2.sh.e255088:ERROR: G_getenv(): > Variable LOCATION_NAME not set > ./launch_SGE_grassjob_MODIS_filt2.sh.e256473:ERROR: Unable to make > mapset element .tmp/blade08 ... Lessions learned (see also http://grass.osgeo.org/wiki/Parallel_GRASS_jobs#Hints_for_NFS_users): * Locking problem: lib/init/init.sh #"$ETC/lock" "$lockfile" $$ is not NFS safe. A solution is to "lockfile" from the procmail software: lockfile "$lockfile" * there are other spurious NFS race conditions in lib/init/init.sh which I could not identify. Solution: Don't use this start script at all! Instead, define the GRASS environment by setting the needed variables, for this see http://grass.osgeo.org/wiki/GRASS_and_Shell#Automated_batch_jobs:_Setting_the_GRASS_environmental_variables The procedure how to set up jobs on a Grid Engine cluster I have now documented at: http://grass.osgeo.org/wiki/Parallel_GRASS_jobs#Grid_Engine cheers Markus _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
