Hi All ,

This is an production issue and i need an urgent help on this case.

In my environment i am having exchange server 2013 in DAG extended with three sites.On that i am having two mailbox servers in the production site and one mailbox server in remaining two sites.

we have mounted all the mailbox databases in one production mailbox server.Those databases are present in LUN mapped to the production mailbox servers from SAN storage.

Issue : 

Few of the mailbox databases are occupying too much of size on the LUN than it's original size.

Say for instance i have kept the mailbox database called "test" which is present on the LUN with the size of 190 GB.On that whole space the mailbox database is occupying only 100GB but on the diskmgmt and also on the explorer it is showing only the free space as 17 GB.

Finally we have run the below mentioned command and found that the used and allocated shadow storage is occupying the size around 34 GB.

Attached snap for your reference : 

Question : How to reclaim the space occupied by the shadow copy storage to the LUN ? If possible someone tell me why this issue is happe

Hi,

According to my research and technology, its caused by Volume Shadow Copy Service which is used to backup infrastructure for the Microsoft operation systems, as well as a mechanism for creating consistent point-in-time copies of data known as shadow copies.
We can use VssAdmin to create, delete, and list information about shadow copies. More details about Volume Shadow Copy Service, for your reference:
https://technet.microsoft.com/en-us/library/ee923636(v=ws.10).aspx

Besides, this issue may be related to Windows server. I recommend you to contact to Windows Server Team so that you can get more professional suggestions, please refer to:
https://social.technet.microsoft.com/Forums/windowsserver/en-US/home?category=windowsserver

Thanks