Hyper-V Replication (Disk write speed Problem)

[tsangouabeka]

Hello, I work in a small software publishing business and I undertake to deploy our solutions in virtual servers.

For this first time I deployed two Hyper-V in workgroup with a single VM (virtual machine ), the replication happens perfectly.

My problem:
-the disk writing rate on the Hyper-V is about 900 MB / s
-the disk writing rate in the VM before enabling replication is about 800 MB / s
-the writing rate in the VM disk after enabling replication down to about 250 MB / s

I tried using a VM of in 1st and in 2nd generation, I observed the same differences ...

But the disk read speed that is about 1300 MB / s in the Hyper-V, remains substantially correct in the VM ( than 1100 Mb / s in all cases).

The problem is the disk write speed that drops drastically in VM after that the réplication is enabled.

Does anyone have an idea of the cause of this huge drop ?

Best regards

 

[MiniKnight]

Is the VM fully replicated when you see 250 MB/s? Sometimes the initial replication can take time and lower performance during the initial sync.

 

[tsangouabeka]

Yes, I launch AS SSD BENCHMARK tool after the initial VM replication is fully completed.
Thanks

 

[tsangouabeka]

The replication is every 30 sec

 

[tsangouabeka]

Tried with 15minutes setting => same result

Try setting to 15 minutes and see what happens.

 

[cesmith9999]

Check your network settings. I just increased my copy speeds copying VM's from my old server to my new 2016 Tp4 server.

the settings that I changed are I maxed out receive/transmit buffers and maxed out the RSS queues.

What this did was copy 1.7 TB in 4 hours over a 1 GB link. before the settings were changed, it took more than 24 hours to copy the files over to the new server.

Chris

 

[tsangouabeka]

The problem I have is the fillowing:
The disk write speed drops down drastically in the VM after that the replication is enabled.
- Before I enable the Hyper-V replication, I have about 800 MB/s
- After I enable the Hyper-V replication, I have about 250 MB/s even if I pause the replication
If I remove the replication, I recover the 800MB/s disk write speed