Low transfer speed on 10g cable

[Piiba]

Hi everyone, i have a TS-673A in raid 5 with 1tb of cache, and a dual 10g expansion slot.
It is connected at internet with a simple 1g cable on one of his two network port and directly to 1 pc with a 10g baseT cable.
I use the nas for video storage.
First, the cache are 2 nvme drives 1tb each in raid and set at all I/O, so 1tb cache read/write, with 50% over-provisioning.
The pc is connected at internet with a simple lan cable to a switch and directly connected to the nas with a 10g cable. I set the network priority at 1 for the 10g cable and 2 for the internet cable, and it works.
The problem is, when i try to copy some video footage form the pc (the footage are stored in a sata3 ssd) to the nas i get initial speed of 500MB/s, but after a couple of Gb transfered, the speed drop below 100MB/s.
I set manually the connection between the nas and the pc, same gateway and subnet mask. The network card on the pc is an Asus XG-C100C, with jumpo packets set to 9014 bytes.

What could it be the problem?
Thx to all!

[dolbyman]

test it with cache disabled..lots of past discussions about cache slowing transfers down, especially sequential ones

[Piiba]

If i disable the cache i have even worst performance...
Is it possible to set a storage pool with the 2 nvme in raid and then set a daily backup to the main hdd storagte pool?

[ritters]

Are you sure to have STP enabled on your switch?

[dolbyman]

If i disable the cache i have even worst performance...
Is it possible to set a storage pool with the 2 nvme in raid and then set a daily backup to the main hdd storagte pool?

6 spinning disks in any raid should easily go over 100MB/s with sequential tasks, of cource you can set the nvme as storage, try it

[Piiba]

the 10g connection is direct between the nas and the pc, because i don't have a 10g switch.
Anyway, i don't know if i can enable the stp in the switch, it's a simple netgeat with 8 port gigabit.
That's why i set a higher network priority on the 10g connection.

[ritters]

I could imagine that you have a loop in your network and it is mainly busy with itself.

[dolbyman]

Try the 10G connection with a dedicated subnet (static IP,s for NAS and client), do not fumble around with priorities.

Then use that subnet to mount shares on your client and try again

[Piiba]

I could imagine that you have a loop in your network and it is mainly busy with itself.

And how can i solve this? I try to disable the network card connected at internet in the pc, so i should had no loop at all, but i have the same problem. With or without cache the transfer speed start good, and then drop down after a couple of seconds.
Qnap software says the disk are good.
If i try to read from the nas (so copy something from the nas to the pc) the transfer speed is much more consistent, from 150 to 200 mb/s without the cache.
Curiously, if i enable the cache in write only, i got the max transfer speed without dropdown! I will not have super fast read but i use the nas mostly as archive, not much for edit video on it.
Also, i see that if i enable the cache in read/write mode, the nvme disk are writing and reading at the same times at 100%, even if i only write on the cache (so coping file from the pc to the nas). Why this is happening? Could be this the cause of the bad transfer speed?

[Piiba]

Try the 10G connection with a dedicated subnet (static IP,s for NAS and client), do not fumble around with priorities.

Then use that subnet to mount shares on your client and try again

Yeah the 10g connection is already set in this way.

[dolbyman]

Then there is no need for any priority, file transfers work over a different subnet

Please disclose the setup fully (no need to censor private ranges)

[Piiba]

the 10g port on the nas:
Static IP: 192.168.1.11
Subnet mask: 255.255.0.0 (/16)
Gateway: 192.168.1.1
Jumbo Frame 9000
Dns 8.8.8.8, 8.8.4.4

The 10g port on the pc:
Static IP: 192.168.1.12
Subnet mask: 255.255.0.0
Gateway: 192.168.1.1
Jumbo packet 9014
DNS 8.8.8.8, 8.8.4.4

The 1g port on the nas that is connected at internet is
DHCP IP: 192.168.1.120
Subnet mask 255.255.255.0 (0/24)
Gateway: 192.168.1.254
DNS automatic

The 1g port on the nas that is connected at internet is
DHCP IP 192.168.1.52
subnet 255.255.255.0
gateway 192.168.1.254
dns 8.8.8.8, 8.8.4.4

[dolbyman]

Please change to dedicated subnets (not just the subnet mask)

e.g.
regular 1GbE network 192.168.0.0/24 (gateway and DNS set)
10GbE network 192.168.10.0/24 (no need for gateway or DNS)

test again

[Piiba]

thx so much for your help, but i don't understand what i have to change...
What's a dedicated subnet? I can only set ip, subnet mask and gateway and dns

[dolbyman]

Set this

NAS 1GbE port (all DHCP) > connected to general 1GbE switch
NAS 10GbE port (192.168.10.10/255.255.255.0) > connected to PC 10GbE port

PC 1GBE port (all DHCP) > connected to general 1GbE switch
PC 10GbE port (192.168.10.20/255.255.255.0) > connected to NAS 10GbE port

now setup an SMB mount on the PC to \\192.168.10.10\sharename and test the speed