Mac SMB file transfer varies significantly based on mounting direction

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Mac SMB file transfer varies significantly based on mounting direction

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2
Operating system
  1. Linux
  2. macOS
Hello,

I found this forum while searching and it appears nicely done. I have filed a support request with Synology but that can take a while, perhaps someone here has an idea.

I'm testing a scenario to be implemented on our live show productions and have come across an oddity that I can't explain. I'm attempting to transfer files from a NAS to a Mac and the transfer speed varies almost by a factor of two depending on whether I mount the NAS on the Mac via SMB, or mount the Mac on the NAS via CIFS Remote Mount in DSM.

I set up a test scenario with an isolated network. Here are the details -

DS918+, DSM v6.2.3-25426 Update 2, SMB=on, AFP=off
- all transfers from a DSM shared non-encrypted folder to a Target Mac.
No other DSM activity going on, no remote access.
Target Mac - MacOS 10.14.6, transfers via SMB, SMB packet signing=off, SMB local caching=off
Admin Mac - MacOS 10.14.6, SMB packet signing=off, SMB local caching=off
All 1G connections for this test, the production version will be a faster NAS with 10G connections.

Test 1 -
Admin Mac is logged into DSM via Chrome and looking at File Manager but not doing anything.
Target Mac has file sharing off, the NAS folder is mounted on the Target Mac via SMB.
Using Finder, transfer several folders of media files from the NAS to the Target Mac.
Transfer speed varies between 100-110MB/s, not bad for a Mac.
NAS CPU = ~12%

Test 2 -
Admin Mac is logged into DSM via Chrome and looking at File Manager.
Target Mac has file sharing on with only SMB enabled.
Via the Admin Mac - mount the Target Mac on the NAS in DSM as a CIFS Remote Mount.
Via the Admin Mac in DSM transfer the same folders of media files from the NAS to the Target Mac.
Transfer speed varies between 48-65MB/s, not good and odd given Test 1 results. This difference persists between reboots, remounts, etc.
NAS CPU = ~44%

Any idea why this is happening? The Resource Monitor doesn't indicate anything odd except the significant CPU usage when using CIFS Remote Mount.

Thanks,
Hugh
 

Rusty

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So initiator in test1 is the Mac and in test2 is the NAS but the direction of data flow is the same, NAS to Mac.

Guessing this is done all locally using lan ip addresses?

Also for test 2 have you tried to copy data from nas to a mac destination but using ssh session and not the browser? Are speeds the same?
 

fredbert

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Also for test 2 have you tried to copy data from nas to a mac destination but using ssh session and not the browser? Are speeds the same?
This also occurred to me: is the web client (DSM portal/File Station) adding overhead? Does it go through the DSM associated data held in the @eaDir folders even when copying out to remote folder?

Logging in to the NAS with SSH and doing a command line cp may throw up different results.
 

Rusty

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This also occurred to me: is the web client (DSM portal/File Station) adding overhead? Does it go through the DSM associated data held in the @eaDir folders even when copying out to remote folder?
I can attest that there are some "problems" when it comes to speeds while transferring using the web ui, but then again, if I am not remote, I use AFP protocol to transfer all my data. Never have any problems with that method.
 
2
2
Operating system
  1. Linux
  2. macOS
Hello Rusty and fredbert,
Thanks for the responses.

I will try ssh and see if that makes a difference. It won’t work for production as they need a gui but may narrow the issue a bit.

I also wondered about the Admin mac’s involvement in the copy process so for one of the repeat tests, after initiating the copy, I disconnected the Admin Mac. The transfer completed indicating the Admin Mac wasn’t necessary, and it didn’t speed it up.

Interesting thought about afp, I didn’t test that because the vibe from Apple (my opinion) seems to be that smb is the future, I will see how afp does.

It may be a few days before I’m back in that studio but thanks again.
Sincerely,
Hugh
 

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