AX88U weird Wifi NAS performance

[MarkusI]

Hey,

I observe a strange NAS / Wifi issue which I cannot make any sense of.
I have a AX88U with a

• USB HDD attached to its USB3.0 port and a Samba share configured
• A Synology NAS DS215J attached via 1 Gbit LAN

When I connect my laptop (MacBook Air M2) directly via 1 Gb cable, I can max out

• the USB drive with read and write at about 100-110 MB/s
• the NAS with read and write at about 115-117 MB/s (which ich basically the max for GBit-LAN)

On the other hand, when I connect via Wifi AX (connection is always between 900-1200 MBits), I measure the following

• about 90-95 MB/s reading from USB, about 35-40 MB/s when writing
• about 60 MB/s reading from NAS, 30-35 MB/s when writing

These results are reproducible and I cannot make sense out of them

1. the NAS is the faster system, both reading and writing, when connected via LAN, but over Wifi, the USB is noticeably faster
2. reading at about 95 MB/s from USB most likely hits the theoretical Wifi bandwidth, but why doesn't the NAS achieve the same?
3. why does writing via wifi only reach 40-50% throughput compared to reading?
4. --> Addition to 3.: if I copy a file to USB and NAS at the same time, the bandwidth usage goes up to 70-75 MB/s, which is still less than expected but shows there is no Wifi bottleneck reached when writing to one device

By the way:

• NAS CPU utilisation 30-40%
• AX88U CPU utilisation negligible

Any idea what could be the reason or how to track the issue down?

Thanks
Markus

 

[L&LD]

I don't see any issues here.

The NAS has HDDs while the MBA is solid state.

An Ethernet (LAN) connection is full duplex. WiFi isn't.

Additionally, WiFi has much more error correction happening.

Add all the above points up, and your results are in the expected range.

 

[drabisan]

+1 to L&D insights.
And I would argue a 8yo J series Synology can actually write at 1G linerate even when laptop is wired. It's been too many years since I had a J series, but those are always heavily underpowered and even reading at 1G it's not trivial. Faster models can do 1G consistently.

Speed you are getting are not bad by all means.
You could get slightly higher if you're optimizing wifi channels, but that's far from trivial. My old AC linux laptop could do about 35MB/s. An 5GHz AX model can do slightly better, about 50-55MB/s, but there are no interference whatsoever. A 6GHz adapter reaches 1G to/from my + series Synology.

 

[MarkusI]

Hey,

thanks for your feedback.
I am not certain, if I get your points, though.

As mentioned,
a) my NAS is easily able to read and write at about 115 MB/s, so the speed of the NAS is not the issue (not theoretically, but measured when wired)
b) my Wifi is easily (also measured) able to provide about 95 MB/s down and 75 MB/s upstream.

So, since neither my NAS can be the bottleneck, nor the Wifi, I don't get why my NAS (being able to provide 115MB/s both ways) is not able to deliver / receive more than 60 / 35 MB/s via Wifi (even if the wifi is well capable - measured - of 95/75)

Where did I miss the point?
Thx
Markus

 

[MarkusI]

Hey again,

so, I now added a USB-3.2 2,5 Gbit ethernet dongle to my NAS and am now able to max out the HDDs at about 160MB/sec when downloading with two Gbit-cablebound laptops in parallel.

The NAS is not the issue.
Also, I consistently get 80MB/sec and above when either reading from the router-attached USB drive or if downloading from different sources in parallel.

So, I would expect to get at least 80 MB/sec when reading from the NAS, but I don't. 60-70 at most.
But I can squeeze more though the wifi if I download from multiple sources at once (e.g. USB + NAS).

Help!
Markus