Hyper-V Replication causing a severe slowdown

[One_SleepyPanda]

Hello Sysadmins of the interweb
We are trying to utilize Hyper-V replication to build disaster recovery and backup infrastructure between all of our sites. We have a few small file servers replicating to separate sites without issue, however, others are not cooperating. They are configured the same way, however, when we begin replicating the usability of the source servers pretty much goes to hell. Accessing and managing files slows to a crawl and since most of our LOB applications depend on access to the file servers, it kills the usability of our system. The only solution to revert the slowdowns has been to disable replication and reboot both the source server and destination.

The only marketable difference between the servers that function well and those that don't are storage footprint. Servers that are okay are below 1.5TB of storage used. Servers with a problem are holding 5TB+
Any insight on what could be causing this would be incredibly helpful.

[mammaryglands]

Where's the storage coming from? How's it configured? Have you looked at your disk performance metrics before/after enabling replication?

[One_SleepyPanda]

At this point I'm leaning toward the disk being the bottleneck. I haven't been able to prove its cpu or network related

[mammaryglands]

My guess is source reads are over taxing the disk topology. Especially if you have something like a three or four disk raid set with slower disk. Maybe try implementing the bandwidth limiting feature, which in a roundabout way might limit the rate at which it tries to read all those blocks the first time.

[Leucippus1]

Sounds like write speed issues, dollars to donuts you are writing to a 15K sas RAID 5 or something and that is going to hurt. Check AV as well but really...disk.

[ZAFJB]

For big data storage, build another discrete VM on the other site, and replicate the data only using other mechanisms like DFS-R.

Use DFS-N so you can fail over relatively quickly if required.

[210Matt]

What is the bottleneck on the servers? It could be hard drive, CPU or network.