SMB transfer unreliable - frequent drop of the connection to my NAS during Time Machine backup
Hi,
after two weeks of testing I am now sure that either my iMac Pro or the XR500 are causing unreliable SMB transfers.
I use the 5GHz band through one wall, but only about 1m away from the router (max. signal level, -41dBm, noise level -93dBm).
I found that after around 1-3 hours of streaming, the connection breaks temporarily and the iMac Pro cannot find the NAS anymore. This happens only for a very short time, then the connection is good again. I just found it in the transfer logs, that the target could not be reached anymore. This causes the backup to fail.
Using an ethernet cable completely fixed the issue.
As this problem occurs on multiple of my computers when using lengthy transfers (SMB) this looks more like a router WiFi issue than a computer related problem. On the router only the 5GHz WiFi is active and I am not using any of the reserved channels (currently channel 36 / 40MHz bandwidth). I also use a fixed IP for my iMac. The router has the latest firmware.
What could be causing such issues? Memory leak? Settings?
Re: SMB transfer unreliable - frequent drop of the connection to my NAS during Time Machine backup
When the issue occurs do you notice any disconnect issues on other devices? Are there any WiFi networks in your area? Could be wireless contention causing the issue briefly, use a WiFI analyzer to find the least congested channel and see if that helps. Does it occur on 2.4GHz at all?
Re: SMB transfer unreliable - frequent drop of the connection to my NAS during Time Machine backup
Hi,
no, I did not notice disconnect on other devices. Interference is not very likely (see attached spectrum measurement). Very rarely a second user is also on channel 36, but at a very low level.
I noticed that it usually needs a transfer of a few 100GBytes for the disconnect to occur. What is especially strange, is that the connection recovers very fast after that. I only could find it through log messages - in this case I tried copying to a disk image using Superduper, which clearly indicated that disconnect on the target side in its log after failure. Time machine only indicated a transfer error not telling on which side it happened.
I am not using 2.4GHz at all on the XR500 as it is simply too slow and as you can see far too congested in my area (Picture of spectrum in my area).
