[MapServer-users] A PROJ_DATA related issue with MS 8.6

[Rahkonen Jukka]

Hi,

We tried to upgrade into MapServer 8.6 but we had to revert because the GetMap requests begun to fail occasionally.  Unfortunately the issue appeared only in the production environment. Now we are a bit lost because in the test environment we do not get errors, and the environment that shows the errors cannot possibly be used for testing.

The error appears so that after lots of succesful request lots of subsequent request fail because MapServer can't find PROJ_DATA any more.
When we switched into MS 8.6 we also changed the PROJ_DATA configuration into the config file, as ENV block.  Before that PROJ_DATA was set in each mapfile separately.

Summary about our situation

- Production server is a physical RHEL server with 64 cores
- Test server is a virtual RHEL server
- Both servers were running MapServer 8.6 on same versions of Apache HTTPD mod_fcgid
- Every now and then PROJ_DATA got lost on the production server, but never on the test server
- PROJ_DATA for MapServer 8.6 was configured in a CONFIG file
- layers are mostly raster layers, so GDAL is also involved

We plan to test if moving PROJ_DATA configuration back into mapfiles could resolve the issue, but unfortunately the next possibility to make the test is weeks ahead. Meanwhile we would like to know if other users have faced similar issues. Also, if someone has any idea about what goes wrong it could help us to start testing the right things. Judging be the behavior it feels like sometimes a new fast-cgi process does not get the information about the location of the PROJ_DATA directory. But why this would happen only on the procuction server (physical) but not on the test server (virtual) is a mystery.

-Jukka Rahkonen-