Hyper-V on Windows Server 2022 - vSAN replication performance

[Electrum]

Hello,

I have a 2 node Hyper-V cluster running on Windows Server 2022. Both devices are directly connected to each other. Their specs are:

Dell R740XD
2x Xeon Gold 6134
384 GB of ram
PERC H730P
Mellanox Connect-X4 25G


MTU has been set to 9014. However, I am seeing replication barely go above ~1.5G on the dedicated replication interface. I temporarily allowed Starwind to utilize the 10G interfaces on these servers as well, and I am seeing equal performance on those as I am on the 25G interfaces.

I'm running the latest Mellanox drivers, and multi-threaded iperf tests should 9~15 Gbit, the CPU is barely taxed typically idling at ~10%. What can I do to improve replication speed?

[yaroslav (staff)]

Replication is not only about the link between the nodes but also about protocol and storage. What is the underlying storage there?
p.s. iperf, especially iperf3, has issues with maxing out 25+ GBE bandwidth with one job.

[Electrum]

Hello,
The datastore is composed of 4x Samsung SSD 870 EVO SSDs, in RAID 10 (both sides).

[yaroslav (staff)]

Greetings,

I'd say that 1.5 Gbps sequentials are not bad, given that all you have for performance is a single iSCSI session.
p.s. Those are consumer disks, if I am not mistaken. Be careful with them.

[Electrum]

Hello,

Fair enough, just wanted to verify. Yes, they are consumer-grade, this is for my home lab. I am slowly phasing them out with Intel enterprise drives.

[yaroslav (staff)]

For a home lab should be OK.
I just had so much "fun" with consumer-grade disks falling out of MDADM/failing apart while rebuilding or checking.