Slow SMB shares, any ideas?

[nquinn]

I'm trying to copy files from my macbook (macOS monterey) to a small mini PC.

Nothing about the hardware chain itself is slow:

- 2021 macbook pro 16" - (2x2 wi-fi 6). Tx connected rate showing 833Mbps (>100MB/s) and speedtest/etc easily hits 300Mbps+
- wi-fi 5 802.11ac (3x3) access pointed.
- miniPC is a Windows 11 machine with a shared network folder
- devices are like 10 feet away from each other

When copying a file to the network share, i'm only getting something like 5-6 MB/s (40Mbps), or roughly 1/200th the speed possible. Maybe 1/100th if you assume half duplex or whatever.

What could be going wrong here?
- mini PC has a very fast 6900hx cpu and screaming fast NVME drive
- Windows is running NTFS of course. I'm wondering if SMB is choking in the APFS -> NTFS conversion over SMB? Might try to create a sparse bundle and copy to that to see if it helps? EDIT: Sparse bundle not much better. Hit maybe 10MB/s, nowhere near 100MB/s.

Anything else that might be going on? Windows or mac not using full SMB3 vs SMB1? Other?
EDIT: Another updated. SMButils is showing it using:

SMB_VERSION SMB_3.1.1

So... not a v1 issue.

 

[rm5]

This is very weird. I am no computer/networking expert, but let me give it a shot:

1. Are both devices plugged into Ethernet?
2. Is the protocol on both machines the same (i.e. using the same service)?
3. Are the access points far away?

I experienced excruciatingly slow transfer speeds when I first got my M1 MBA, but this has since been fixed just by plugging into ethernet. I have 250 Mb/s download on speedtest.net which is slower than yours and still transfers at nearly 200 MB/s (b/c of spinning hard drives in the servers).

The NTFS thing might be the problem. Even transferring from my TrueNAS systems on a Mac is exponentially faster than on a PC, even when plugged into ethernet, so yes, I've experienced that part of your problem.

 

[rm5]

After a little more thought, it's definitely the "choking" as you call it of APFS to NTFS/SMB. Maybe install something like TrueNAS on a second drive/partition and see if it's any faster? That's my recommendation. The speed of your network should not matter one bit as long as the machines are wired.

 

[nquinn]

After a little more thought, it's definitely the "choking" as you call it of APFS to NTFS/SMB. Maybe install something like TrueNAS on a second drive/partition and see if it's any faster? That's my recommendation. The speed of your network should not matter one bit as long as the machines are wired.

I tried creating a sparse bundle on the Windows 11 machine to write to so it's more like APFS -> APFS but it didn't really help. Still peaking around 11MB/s.

Both are on wi-fi (one is a macbook so will always just be on wi-fi. I could put the other on 1Gbps ethernet if I want but it has no issues with speedtest/etc).

 

[mzeb]

My first suspicion is always wifi when seeing slow speeds. There's a lot that can cause issues and speed tests don't actually do a very good job of measuring real world performance as they can fill the data in every packet. If you have a chatty protocol (like SMB) then latency is usually your issue.

Check your latency with the ping command on the Mac to the mini pc. For good performance on a LAN you should be seeing single digit latency. If you aren't that is almost guaranteed your issue. (You need all the control packets to have a short turnaround so that the data packets can shovel the actual file over).

Alternatively since they are only 10 feet apart try stringing a cable between them and set static IPs on the hardwire NICs. Then mount the share from the PC to the Mac using the static IPs and see what speeds you get. I would put money down that you'll see at least 70% of the theoretical maximum. If you do we can be sure it isn't the hardware or software on either machine but the way the network is configured.

One last thing. Tools like iometer (http://www.iometer.org/) can help you check the performance of shares for various file loads (I know the site isn't secure and that is because the devs aren't security folks, they're hardware folks so you do you for your trust of it). TM backups do a lot of small writes which is tough for networks that are high latency. You can use this to get more detailed testing of your setup.

I have a similar setup with a Windows server 2019 box that shares files and do see go performance over both wires and wifi. If things look OK for your latency and things over ethernet don't work out we can dig in a bit more but this is where I'd start.

 

[nquinn]

Will experiment with ethernet/etc, but I don't intend to use ethernet with this since the common scenario is laptop on my lap on couch/in bedroom and htpc running in living room.

Also definitely not a small file size issue. My tests have all been with 1gb-10gb large files.

Ping is 3-7ms.

 

[Marsikus]

I blame SMB! Years ago I often had to install 3rd party FTP server on Windows machines to overcome issues of SMB.

 

[nquinn]

I found this synology guide for troubleshooting slow SMB. Might try a few tonight:

What can I do when the file transfer via Windows (SMB/CIFS) is slow? - Synology Knowledge Center

Synology Knowledge Center offers comprehensive support, providing answers to frequently asked questions, troubleshooting steps, software tutorials, and all the technical documentation you may need.

kb.synology.com

Most are Windows related though - I might have to research handling both macOS and Windows aspects of it. Probably will start with turning off signing. No way i'll disable 'Enable data checksum for advanced integrity' though - I barely trust SMB as it is.