ZFSSA with compress (question for compress when it requested read i/o from compressed stored data on

Hi, All.

I would like to ask the compress option on ZFSSA.
I have a disk space issue, so I used to set the ZFSSA with following option when I created the shares/LUNs.
Please recommend about it, if there be any problems.

#. Customer's environment.
     1. Vmware ESX (VDI soluion)
     2. FC connection to ZFSSA. (ZFSSA served as SAN).

#. ZFSSA configuration.
     1. 64K blocksize (Vmware OS host is Windows)
     2. Mirror profile of ZFSSA storage.
     3. Compress option with LZJB. (fastest compress)
     4. Disk is 900GB (24ea). No logzila.
     5. FC connection between VMware Sever and storage.

Here are questions.

Q1.
When the data write on disk, the compress was working as I knew.