replica about VDI deploy

Hi, All

I used VMware View 5.0 with linked clone to deploy my VDI pool.

View composer is installed on vCenter server. After deploying desktop, I found one virtual os named replicaXXXXXX will be automatically created under my vCenter.

And the virtual os is always poweroff. I wonder what the replica is and its usage? For details, pls refer attached picture, Thanks in advanced.