Vsan write iops question

[ManivelR]

Hi Team 

I'm currently evaluating the hci benchmark testing with multiple profiles. 

I see, read iops is excellent but write iops is very very less under cluster performance tab. 

Vsan nic may be the bottleneck? 

I like to update the firmware of nic. 

I use, mellanox connect x-6 dual port 100g nics. 

Thanks, 

Manivel RR

[depping]

Okay? What is the question here?

[ManivelR]

Thanks for the response.

We use OSA architecture with VSAN 8. We use the following dual port 100G NIC for VSAN traffic(enabled with RDMA).

Mellanox Technologies ConnectX-6 Dx EN NIC; 100GbE; dual-port QSFP56; PCIe4.0 x16; (MCX623106AN-CDA).

I don't know why write IOPS is very low.

I don't know where the problem ?

[depping]

It is very likely that that is a networking issue indeed. although I would suspect that reads also come across the network in most cases? Anyway, it is hard to say what is causing this. Why not file an SR and get help from our support team? As these numbers are just ridiculously low indeed, and point to some kind of misconfiguration.

[TheBobkin]

@ManivelR Are you sure the screenshot you shared isn't while testing with a 100% read workload?

If there was a problem resulting in low write throughput then you would see huge latency for the write IOPS in the graph panels beside/below the ones you shared - what do these show?

[ManivelR]

Hi Bobkin,

yes.We reinitated the test with 100 % write and random.It crossed above 300000 IOPS which is ok.During the test,95th percentile latency only goes above 15ms.

As I'm using PM9A3 NVME SSD disks,the results are ok.As this SSD is completely read intensive disk,read IOPS goes up to 1 milllion,however write IOPS goes up to 300000.

Im also following up with vsan performance team for the same.I need to know the reference test results to match the performance with my current setup

I dont know,whether these values are good enough or is is not up to the mark?

From VSAN proactive test(network),my mellanox 100 G NIC pushes max 30000 Mbps only.What can be max throughput ?Im still not sure..

Thanks,

Manivel RR

[depping]

You have a 100Gbps switching infra as well then?

[depping]

and 300k write iops is decent considering the devices you use, I would not be concerned about that at all.

[ManivelR]

Yes Depping.

We use 100 G support cisco sitches

[ManivelR]

ok thanks depping.