A few months back, my Synology NAS (DS2413+) started having some poor performance over the network – it wasnt horrendous – but it was noticeable. Speeds during transfer were generally fine, but simple cut/paste operations took longer than expected – and moving large files to the NAS seemed to swap between poor and decent transfer rates. It is connected to the networked via a 2 x 1GB bond, up to date firmware wise etc etc… Its been rock-solid and awesome for many year prior to this (overall, the synology experience has been generally awesome)
After a while of not really worrying about it too much, i got little annoyed with the performance and decided to look into further…. basic logging showed no issues, resource monitor showed no issue, the switch showed no issues…
On the NAS, I went into control panel | File Services | SMB | Advanced settings and noticed the “maximum SMB protocol” was set to “SMB2 and Large MTU”…. given that everything on the network is now Server 2019 or Windows 10 – there was no reason not to use SMB3…. i was also a little perturbed that SMB3 was not the default setting for “maximum”. I also changed the minimum to “SMB2 with large MTU” – even though i don’t think i have any SMB2 devices left on the network.
Once this was changed, all was good again… not sure if there was a patch on the MS side which resulted in this or if its a synology thing… or some type of strange combo…. either way – the Synology is something i rarely check (outside of firmware updates) – and changing to SMB3 was always going to be a good thing.