I have Oracle Unbreakable Linux 6.5 which runs Oracle ERP application & Database it has three VHDs 80 GB , 600 GB and 120 GB on daily basis it creates RMAN backup approx 32 GB which stores on 120 GB VHD.This VM has more READ operations and around 1 MB / 1 Mins Write Operation other than Backup.
I have enable Hyper-V Replication on this machine with 60 Sec Cycle Exclude 120 GB VHD where RMAN data places but i have found that replication is not going on normal.
I can see that hyper-V replication fully utilizing 4 MB to 5 MB.
My Question :
1.If i excluded 120 GB VHD and i have very little write operations on replicating drives so why replication is not normal
2.Is read operations have impact on replication
Check the avhdx files in the folder of the VM - when this files are growing quite fast.
You can also utilize perfmon to see on which of the VM files most of the data get's written over time (it's not a technical measurement - just to see wheter it's the 80G or 600G vdisk).
Running windows with replication an important factor is pagefile usage - replica detects/copies any write, no matter if it's always on the same part of a virtual disk. Writing to some kind of pagefile (swap) or tempdb will therefore result in additional data that has to be replicated.
There are recommendations to exclude drives with swap/pagefile from replication - this would require to create an additional disk an relocate the data to this disk if possible. Afterwards you may exclude the drive from replication.