Snapshot needs to consolidate frequently

All,

We are using BE2014 on Windows server 2008 R2 SE(SP1) physical server, all backup servers are running on iESX5.5 and we take backup 10 VM guests servers. We take full backup on Friday and differential backup from Monday to Thursday. Our Lotus domino server has huge disk volume(800GB) for Notes database and the server has got alert as disk consolidation needed frequently and the server is very slow.

Has anyone experienced same problem?