Piwik is not logging the tracking data on server. But It is working on localhost

Piwik is not logging the tracking data on server. But It is working on localhost.
In dashboard, we are not getting any tracking/analytics data. I checked my database, It is making entries only in the “log_action” table. Entries are not happening in any other table.
If i check ‘my system check’ page, It is giving me only a warning for filesystem, that, "Your server is using an NFS filesystem.This means Piwik will be extremely slow when using file based sessions."
What to do ?