I have a VM running in ESXi with Windows Server 2019 running some application that writes data to drive Z (not the system disk, NTFS, 500GB capacity).
When looking in disk properties I see the disk has 50GB free but when summing up the file sizes on the disk, they sum to 407.5GB allocated (505.2 total size - some folders are compressed).. Because 407GB is allocated I should have about 90GB free but I only see 50GB. When I restart the server, the disk space returns to normal and I have 90Gb free and it starts to shrink again.
I thought about VSS but running
VSSADMIN LIST SHADOWSTORAGE
says that 0 bytes are allocated on drive Z
I also checked with TreeSize (ran as admin) and the total allocated disk is 407.5GB
I also tried using Nirsoft Alternate Data Stream viewer to make sure no app is holding some data but nothing comes up.
Apart from rebooting the server every night to free the disk space, What am I missing? Could it be related to the fact that some folders are compressed?