Add environment variable to create all temp-files at a user-defined location (outside the mapsets)

[sbl]

Some Network Attached Storage (NAS) filers with snapshot backup on volume level do not allow to exclude specific file types or directories to be excluded from backup. If GRASS data DB is stored on such a storage system, temporary files can grow the snapshot file significantly until a point where available space is used up by backup files (how fast that happens depends on the snapshot frequency of course, and the time they are preserved).

Currently, it is not possible to redirect all temporary data to other storage locations. Would be great to have an environment variable that allows to specify a path (directory) where all temporary data will be stored.

Might be necessary to make a subdirectory per mapset within that directory... (Maybe an 8.0 thing?)

[neteler]

As a workaround you could simply replace the location/mapset/.tmp/ with a link to a directory on SSD.

However, from the planning document:

​https://trac.osgeo.org/grass/wiki/Grass8Planning#Rasterlibrary

• "implement GRASS_RASTER_TMPDIR_MAPSET like it exists for vector data (GRASS_VECTOR_TMPDIR_MAPSET), i.e. change all .tmp/ to variable in source code in init/grass.py, gis/open.c, gis/file_name.c, raster library"

Maybe to be worked out in more detail but for sure very important (we frequently face the same issue).

[sbl]

Consider also: ​https://trac.osgeo.org/grass/ticket/3857#comment:4

[martinl]

Such variable is currently implemented only for vector library (GRASS_VECTOR_TMPDIR_MAPSET), see also related discussion, ​https://lists.osgeo.org/pipermail/grass-dev/2015-June/075220.html

[neteler]

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[neteler]

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[neteler]

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