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

  • How did you check that replication is "not normal"? Use Get-VMReplication in Powershell to check Replication Health and State. – duenni Mar 2 '16 at 11:08

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.

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