You can refer the below HPE Support Community forum on the automatic space reclaim topic and it was that time ESX 6.5 but same logic still applies for ESX 6.7 as well,
https://community.hpe.com/t5/msa-storage/msa2042-unmap-on-esx6-5/td-p/6970665#.XzKzDigzaUk
Now coming to below command that you have executed,
"
I ran the folowing command on one of the ESXi hosts cli:
esxcli storage vmfs unmap -u 5c5c5xxx-7291e540-xxx-5480xxx23b90
"
Is "UUID: 5c5c5xxx-7291e540-xxx-5480xxx23b90" represents MSA volume named "MSA2050-SAS" what we are dealing with?
If MSA base and ESX base both are base 2 then it's really an issue but I can't comment further until we check MSA volume "MSA2050-SAS" in ESX host at the datastore level in live system cause we need to understand what all vmdk files accumulating 5.99TB size in ESX host which is actually consuming 4443.7GiB in MSA volume side.
Hope this helps!
Regards
Subhajit
I am an HPE employee
If you feel this was helpful please click the KUDOS! thumb below!
*************************************************************************