That´s it - solved!

Thx & Cheers
Sasa

here is the output and it is 100% used, right!

Should I remove all from /var/spool/exim4/input? What exact redirect do you recommend?

Can you check df -i to see if you have inodes remaining?

Here is a thread where someone ran out of inodes: https://forum.infiniteautomation.com/topic/2556/mango-not-starting-disk-is-full

The issue was traced to a cron script creating a lot of files in /var/spool/exim4/input and could be fixed by updating /etc/cron.d/system-info to redirect all output like >/dev/null 2>&1

ERROR 2017-05-13 11:58:46,511 (com.infiniteautomation.nosql.MangoNoSqlBatchWriteBehind.execute:110) - Error saving point value. 
org.tinytsdb.TinyTSDBException: java.io.IOException: No space left on device
	at org.tinytsdb.impl.TinyTSDBImpl.write(TinyTSDBImpl.java:309)
	at com.infiniteautomation.nosql.MangoNoSqlPointValueDao.savePointValueSync(MangoNoSqlPointValueDao.java:65)
	at com.infiniteautomation.nosql.MangoNoSqlBatchWriteBehind.execute(MangoNoSqlBatchWriteBehind.java:96)
	at com.serotonin.m2m2.rt.maint.BackgroundProcessing$1.run(BackgroundProcessing.java:54)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.IOException: No space left on device
	at java.io.UnixFileSystem.createFileExclusively(Native Method)
	at java.io.File.createNewFile(File.java:1012)
	at org.tinytsdb.impl.Shard.ensureDirty(Shard.java:325)
	at org.tinytsdb.impl.Series.write(Series.java:160)
	at org.tinytsdb.impl.Series.write(Series.java:145)
	at org.tinytsdb.impl.TinyTSDBImpl.write(TinyTSDBImpl.java:301)
	... 6 more