ODY1980 Author

Level 1

9 points

Imac Pro - Crash when copy over 200GB on SMB !?

Hello, I have a really strange problem - since I upgrade to my new imac pro.

I really hoped for the 10.13.3 update - because it mentioned to fix SMB problems with crashes - but sadly it didn't help.

The problem I have is the following:

When I copy my VM Ware Folder (via 1Gbps ethernet cable) as a backup to a synology via SMB as soon as I hit around 200GB over the network the network of the imac stalls. No more receiving/sending - no more possibility to ping - even trying to disable and reenable the network doesn't work. No errors shown in any network utlity of bad packets etc. If I just wait then the mac just reboots itself without any error message and comes back.

What I tried so far:

1) Another imac Pro - same issue!
2) Even though the lockup happens on the imac (so it can't be solely related to the network itself) i tried to check if there is anything wrong in the network. Changed router, Change switch, Changed network cable etc. ! However with an old imac I can copy the file on the same line easily without any issues.

3) Tried different SMB settings 2.0 / 3.0 / disabled signing etc. - everything without any help.

For me its clear there is a severe driver issue with the new 10GB network port on the imac pros - but how can I truly identify the issue and report it to apple - so they take me serious without doing the normal troubleshooting...

If anyone has an idea, I would be more than happy to hear it 🙂

Like i said if i for example copy 50GB and then later 150GB - it will happen at 150GB - so it look like something is running full in a some kind of buffer at 200GB copy over network to smb.

Kind regards,
Oliver

macOS High Sierra (10.13.3), null

Posted on Jan 24, 2018 12:29 AM

Top-ranking reply

ODY1980 Author

Level 1

9 points

Posted on Jan 24, 2018 8:44 AM

Hey there - with your help I was finally able to find the issue.

Manually did not help me in the beginning because 1000T was correctly set by automatic. But automatic also sets the full duplex mode to:

full-duplex, flow-control, energy-efficient-ethernet

The problem here is the last option -> energy-efficient-ethernet <- this causes when using the SMB protocol and copying more than 200GB of data to the network to completly crash or stall the imac pro.

So all you need to do is changing it to manual and setting the full duplex to: full-duplex, flow-control

without this energy-efficient-ethernet - this also boosts your network speed by 2-3mb/sec.

I reported this to apple and hopefully they will make a fix with the automatic setting.

Kind regards,

Oliver

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36 replies

Jan 30, 2018 2:58 AM in response to ODY1980

Got the same crash after copying a bunch of gigabytes by SMB.

My default network-setings were by default: "automatic" and without energy-efficient, crash still occures.

Yesterday changed to manual and full-duplex with Flow control, still the same cash happened after copying lots of gigabytes (whatever from/to imac pro <--> NAS or NAS-to-NAS).

Today i'm testing CIFS instead of connecting via SMB to the NAS (to different machines, so these are not the problem...).

At third test option if nothing helps:

Having a USB-C network adapter...

Feb 3, 2018 6:45 AM in response to ODY1980

Very interesting! PLEASE report back with any new information.

Just an FYI, you might want to tell your Apple Support representative, that we're having similar issues with other Mac's transferring to an SMB on High Sierra. Those Macs use the Sonnet 10Gb Twin Ethernet Adapter.

ODY1980 Author

Level 1

9 points

Feb 1, 2018 3:05 PM in response to ODY1980

Now its getting really totally strange... in order to further investigate this issue with an apple engineer - I had to reenable energy efficient ethernet once again so I was able to reproduce it for some diagnosis...

and now... I did reproduce it... but when now switching back to full-duplex, flow control - exactly as it was before its STILL happening!!

So now I know why some of you may not be able to remedy the problem with this change. It seems like that the network adapter is not keeping the settings correctly!!

Long story short, I wanted to help apple to give them log files and reproduce the problem and now its also back on my machine and this option doesn't help it anymore... so to all of you where it works now - just leave it alone 🙂 but that explains at least why it worked for some and others not.

Kind regards,

Oliver

Feb 18, 2018 9:26 PM in response to Nikki Gordon-Bloomfield

I got a replacement iMac Pro and so far it hasn't given me a single kernel panic. I have been using the "sudo sysctl -w net.inet.tcp.tso=0" command from earlier in the thread on every boot, so between the new computer and that command, I am panic-free.

But I have experienced a couple of instances where my networking will just stop entirely and only be remedied by a reboot. One just occurred a couple minutes ago, and I tried pinging my router in Terminal just to see what it said, and it gave me this error:

"ping: sendto: No buffer space available"

Do you know whether this occurred at all when you had your network issues? And has this occurred at all since you got your replacement machine & started using "sudo sysctl -w net.inet.tcp.tso=0" command?

spertti

Level 1

36 points

Jan 24, 2018 9:10 AM in response to ODY1980

Good to hear that you find solution.

I was just about to send screen shot of settings which I have set to solve this 10Gb auto setup problem:

The issue might be that when you set or leave that configure to Auto, network devices might negotiate "new" speed at almost like they will, that can lead all kind of network issues.

ODY1980 Author

Level 1

9 points

Feb 1, 2018 11:19 AM in response to Nikki Gordon-Bloomfield

I still think that we are talking here about 2 different issues! The one which some of us had is directly related to the energy-efficient-ethernet.

But if you say that you are crashing on all protocol types and regardless what network interface used - I am pretty sure this is a completely different issue - especially because it is NOT related to the network adapter itself 🙂.

So maybe you should also contact Apple and get through their diagnostics.

Feb 6, 2018 5:41 AM in response to ODY1980

We did a transfer last night with this command and it seems to have worked! No crashes! Unfortunately though, it has cut our Read/Write speeds in half. From 700/400MBps to 300/250MBps :-(

Anyone else having this reduced speed issue?

Feb 8, 2018 8:44 AM in response to ODY1980

Definitely related to this issue! Roger that on changing things on the fly, but obviously not optimal.

Is there any "reason" you or anyone can think of that would cause things to be slower with TCP.TSO off?

Feb 13, 2018 8:59 AM in response to IndianaPwns

They got my full crash-log and kernel panic report.
We have to wait for one of the next updates, he says. Don't think that Apple is calling -me- to offer a pre-fix or for the "fixed-it message". I am only a ordinary customer... 🙂

The two calls from Apple were suprise and effort enough. Never experienced this with any other big company that they call 'the little man' and overseas talk!
Now they have work to reproduce and fix this cause. Hoping at the next coming High Sierra update. Fingers crossed.

ODY1980 Author

Level 1

9 points

Feb 13, 2018 12:18 PM in response to IndianaPwns

Same here and I have to say it was really nice to see that you get pretty quick someone of a higher level to talk to without too much hassle - especially after I told them that they had a serious issue with the networking adapter in the new imac pro 🙂

Now they have all infos they need to fix it and I am pretty sure they will do it soon enough. I mean this is a serious issue affecting many customers of imac pros - especially since even a simple restore on the imac pro from an SMB drive will cause serious troubles.

I myself invested more than 2 weeks to find the fix and I was already thinking my imac or my network is at fault 🙂

So let's see when they will provide us with a solution and hope they can calm down any customer who is facing this quick. But overall for such a big company it was great to see that their support was really trying to help - also had an oversea calls etc. 🙂

Kind regards,

Oliver

Feb 18, 2018 11:23 PM in response to mustgroove

Yes, this is exact the error. When you wait any longer the iMac will reboot by itself simply by clicking 'empty' on the desktop.
Exact so it happend right before a reboot by tgeh machine itself: First network disconnects, slow(er) response, then this message when sending a ping, then the machine reboots itself.
I think you still have the fault in your new machine. We had to wait for a software fix.

Feb 19, 2018 8:33 AM in response to ODY1980

It's possible my situation might be slightly different though:

1) I'm not getting spontaneous reboots or panics when I lose network connectivity. The network just drops out, and everything seems fine - no slowdowns, no glitching of apps (which is what happened on my last iMac Pro when the network would drop out). Which is definitely better!

2) I *think* I already had set TSO to 0 last night when the network dropped out. I could be wrong (it may have slipped my mind to do it on that particular boot) but I'm pretty sure I had. In which case maybe there's something else going on

Feb 19, 2018 2:54 PM in response to mustgroove

I am in your exact situations...I wonder if this is happening on other Mac's connected to SMB's through High Sierra. I have experienced the random network drops as well with TSO off. Everything is still unreliable at the moment.

Feb 19, 2018 4:08 PM in response to IndianaPwns

Cool thanks - are you just getting dropouts without crashes or kernel panics? Because that's what's happening with me - network drops out, but nothing else is affected, I just need to manually reboot to get the network back. No crashes, no hangs, no kernel panics.

Jan 31, 2018 11:56 AM in response to ODY1980

Great idea! We have a Sonnet Twin 10G Thunderbolt 2 adapter to try...will report back!

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Imac Pro - Crash when copy over 200GB on SMB !?