A few things that I have discovered: I made a call with technical support VMware:
Our statiscis level was to high, level 4, we brought it back to level 1 or 2.
The calculations for the size of de DB was not correct producing losts of MB's in the database.
The problem is still not solved. To solve this I restored a backup of our VCSA, the size of which was /dev/sdb3 about 50% of the volume.
After a while the volume size increased to 75% around 14GB which I think is still to much, because of the statistics level that was set to 0 (turned off).
Then I followed the advice in the KB 2007388
I run truncate table vc.vpx_hist_stat1 truncate table vc.vpx_sample_time1 (and repeated for stat2,3 and 4 / time2,3 and 4)
After truncating these tables the disk space was not given back as free space.
Looking in the tables I see the folowing:
TSIZE Table size in bytes.Table: VC.VPXV_DEVICE_COUNTER tsize 2351583
Table: VC.VPX_EVENT tsize tsize 13439815
Table: VC.VPX_EVENT_ARG tsize 15995147
Table: VC.VPX_STAT_COUNTER tsize 1839357
Table: VC.VPX_TOPN_PAST_DAY tsize 9819056
Total volume is 20GB....where does the space go??
Can you please give me some advice as how to solve this issue and release the extra disk space.