disable smb3 - potential impact?

Question

We want to disable smb3 globally, this is to investigate some performance issues between a client and the powerscale using smb3 encryption. however I want to know what impact this will have for all other clients (1000) accessing various different SMB shares, if we disable SMB 3 using  --revert-support-smb3-encryption, will that terminate all current live smb3 connections, will they just get a brief TCP reconnect at smb2? I have also read in the documentation 'Making SMB encryption configuration changes requires either restarting or refreshing (less intrusive) the SMB server. You can refresh SMB server service by running the command /usr/likewise/bin/lwsm refresh srv on the PowerScale cluster. '. I wanted to know what does refreshing the service do? does that mean users continue on SMB3 until their connection drops and they reconnect at SMB2, or is it forced through? and how is that different from disabling/enabling SMB service? I need to understand if this an activity that should happen out of hours or not.

storageSysAdmin · Accepted Answer

FYI to anyone else, we did the change, had to refresh the service which reloads it so all new connections just have it disabled, its a better graceful way rather than stop/start/restart which would drop all connections. in some cases end user clients wouldn't drop smb3 encryption for sometime, 20mins+ but I suspect that is windows client behaviour keeping the connection running for longer than expected.

saw about 15% performance gain from disabling it site wide, so we probably wont enable it again.

Phil.Lam · Answer

@storageSysAdmin ,  please create SR to find the impact

Isilon

disable smb3 - potential impact?

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