EX4 SMB Connections Randomly Timing Out

Let me see if I can accurately explain my issue here. My network is fairly simple.

WD EX4 –> Asus Router (1GB) –> Windows 7 Laptop (802.11G), Windows 10 Laptop (802.llN), WD Live TV.
WD EX4 (same one as above) –> Asus Router (1GB) –> 1GB Switch (I forget the brand) –> Windows 2012R2 Desktop (1GB), Windows 10 Desktop (1GB),

I work with a lot of video and thus transfer a ton of data too and from the EX4. The problem is that short amounts of Network activity between any machine to the EX4 work fine but if it is a lengthy session or if the session is frequent in a short timeframe, the connection between the EX4 and whichever machine times out. The size of the files seems to make no difference. I can move 1 large file or 100 small files and the result will be the same somewhere along the way in that the file transfer will time out and the connection to the share on the EX4 will be lost. This doesn’t happen every time I move a large file or set of files but it does happen at least 3 or 4 times a day.

The only way I have found to re-establish a connection is to reboot either the machine or the EX4. If the connection has timed out to one machine, the EX4 is still fully accessible by other machines. It will even remain accessible to VM’s running on a machine that can not currently connect to the EX4.

I have tried setting the SMBv preference on the EX4 to 1,2, and 3 while forcing the same version client side on different machines with not effect. I have turned off thumbnail services via ssh on the EX4. I have set SMB connections to persistent client side and disabled the Windows OS from shutting the NICs off to save power.

When the SMB connection times out, other services still function. The EX4 is still pingable from the machine, ftp, ssh, WebDav, etc are all still fully functioning with the machine that can no longer access the shares via SMB.

Also when the problem occurs, it is SMB device wide, not just the share on the EX4 that was being accessed but all 5 shares currently hosted by the EX4.

As a further test, I have moved the same data to and from shares from machine to machine without a single issue. Everything points to something with the EX4 causing the issue.

The Firmware is up to date and this problem has persisted through several firmware versions.

Frankly, I am at a loss here and any assistance would greatly be appreciated. Thank you for your time.

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Hi pmo6,

Maybe you should try contacting WD’s Technical Support about this.

To Contact WD for Technical Support

The link below will allow you to call support.

Thanks for the reply. I actually did a couple years ago when I first purchased this NAS. After much runaround and minimal effort on their part, I was told that since they could not consistently recreate the problem that it must be due something unique about my setup and no cause of the EX4. Funnily the only thing still the same about my setup since then is 1 laptop and the EX4. It appears I have come to a solution to manage the problem, even if it doesn’t truly fix it. I share the following just in case someone else out there is having this issue.

Anyway, I am getting closer to the cause I think. I believe the Ex4 can only handle 10 concurrent smbd sessions. I’ve noted that ftpd can only handle 10 ftpd sessions and one failing of the EX4 is that it doesn’t time out those sessions so if a ftp client doesn’t logout cleanly, then eventually the ftpd service will be locked out rejecting new logins because the max number has been reached. I believe the same is true with smbd in that the EX4 doesn’t kill the unused smbd sessions and just lets them pile up.

So I’ve started paying attention to Top and anecdotally it appears that this is the same with smbd. Once 10 smbd -D processes are reached then it seems the problem starts. To test, I setup a Powershell script to login via SSH and kill all non-active smbd processes and to start a smbd daemon running as root. This runs as a scheduled task every 30 minutes on a Win2012R2 VM. This has been running for 24 hours and I this seems to have “fixed” the issue. I’ve considered setting max connections in smb.conf to confirm but given I’d have to do this everytime the EX4 is rebooted or has an update, I think I’ll just leave it be as long as this continues to keep a band-aid on the issue.