i am planning to install zimbra 8 on VPN hosting with 1000/GB Disk formatted using LVM on Centos 6.3

Centos 6.3 installed with 100 GB of Disk ,i added new drive on my virtual machine and want to mount on /opt for zimbra storage .

/opt ( /dev/sdb) 800GB ( VMDK THin or THick ???? )

i want to ask whether to create Thin or think drive for /opt ? is there any performance effect on zimbra ?