I am having a similar issue as well on 5.5 u1. Nimble storage is showing a free space of 5tb on my lun, VMware is reporting something less. the discrepancy seems to be with the used space. Used space on vsphere is over 9 tb while used space showing on Nimble is showing just over 5 ( taking advantage of compression etc)
this is not happening on Netapp using nfs.
does anyone have any updates on this? Also what happens if we just let VMware report 0 free space? If there is free space on the LUN will VMware still lock and suspend all vms on the volume when it reaches 0 ?