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MOCA 2.5 - Asymmetrical speed

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45263tec

New Around Here
Posted this on reddit but i don't expect much from there for reasons i won't get into.

I have 2 new GoCoax MA2500D MOCA adapters with 2.5GBE switches, cat 6 cable and 2 machines running RTL8125b 2.5GBE network cards.

The problem I'm having is that transfers to the file server write at close to 210MB/s (not great, but good enough) but the read speed is terrible at only 50MB/s.

I have turned off EEE on both machines, MA2500D updated to latest firmware. The MOCA splitters in use are wideband and explicitly MOCA compatible. One holland 3-way moca splitter with a POE filter outside the house, one "starburst" moca compatible 2-way indoors.

I don't expect mega speeds when reading and writing are occurring at the same time, but what could the issue be?

Here's what I tried so far.

  • LOOOONG ethernet cable wiring both machines together = full 2.5gbps speed in both directions.
  • LOOOONG ethernet cable connecting both 2.5Gb switches together = full 2.5gbps speed in both direcitons
  • Both MOCA adapters plugged directly into each machine, same problem.
  • I powered off my cable modem, same problem.

PHY rates in the UI are perfect:
PHY rate (0-1): 3523
PHY rate (1-0): 3531
PHY rate (0-0): 696
PHY rate (1-1): 693

No bad packets

Iperf3 bears out the issue. Using 5 threads with (-P 5):

Client -> File server 2.34 Gbits per second
File server -> Client 556 Mbits per second.

This basically matches what I am getting manually transferring files or running AJA.

Client -> Fileserver: 215 MBytes per second (write)
Fileserver -> Client: 55 MBytes per second (read)


I have seen a couple posts discussing this topic but no one seems to have any answers. Hoping someone has a fix.
 
Last edited:
Your moca network seems fine given the sync rate. Your issue is likely the server read/write or client r/w or protocol used (SMB ?) . The iperf tests should be running from memory only, so disk access would not be in play . Try -p 10 and run it in both directions using reverse switch setting.

When you write 2.5 Gb/sec on the long ethernet cable test - that is the link rate shown for the interface ?
If so, that has nothing to do with the transfer rate except to set an upper bound.
 
Yes this is using SMB. What bothers me is that with both machines connected via ethernet (no MOCA) the transfer rate is pegged at 290-300 something megabytes a second which is what the drives in the file server can do.

-P 10 shows good speed, close to 2.34gbps with a fot of fluctuation but frankly this is not of any use if the file transfers themselves are extremely slow in day to day work. For example, 50MB/s is just not enough to use files live off the file server.
 
That 2.34 Gb/s is a saturated 2.5 link.
if you need real time access in the file, then use direct attached storage as that is the cheapest way to go. TB4 or 3 or maybe a local nvme array if you have enough pci lanes and bandwidth left available.

see the diy nas sub forum.
 

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