Hyper-V Replication - Slow Cycles

Hi All,

I have VM Named as "ERP" Operating System LINUX Machine Placed at Primary Data Center.DR Site Connected with 4 Mbps link

Now this VM Creates Backup Daily on VM Hard disk it self.

We have enable replication on this machine excluding of that drive where backup creates.

but still replication health is in criticial state and replication cycles completely very slowly.

i have a question there are only few GB's chance in this VM machine excluding backup activity which is approx 50 GB.

how can be long pending data so high if changes drive exclude.