My first guess would be the network between the NSD client and NSD server. netstat and ethtool may help to determine where the cause may lie, if it is on the NSD client. Obviously a switch on the network could be another source of the problem. Fred __________________________________________________ Fred Stock | IBM Pittsburgh Lab | 720-430-8821 stockf at us.ibm.com From: "Buterbaugh, Kevin L" <Kevin.Buterbaugh at Vanderbilt.Edu> To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org> Date: 10/04/2018 03:55 PM Subject: [gpfsug-discuss] Long I/O's on client but not on NSD server(s) Sent by: gpfsug-discuss-bounces at spectrumscale.org Hi All, What does it mean if I have a few dozen very long I/O’s (50 - 75 seconds) on a gateway as reported by “mmdiag —iohist” and they all reference two of my eight NSD servers… … but then I go to those 2 NSD servers and I don’t see any long I/O’s at all? In other words, if the problem (this time) were the backend storage, I should see long I/O’s on the NSD servers, right? I’m thinking this indicates that there is some sort of problem with either the client gateway itself or the network in between the gateway and the NSD server(s) … thoughts??? Thanks in advance… — Kevin Buterbaugh - Senior System Administrator Vanderbilt University - Advanced Computing Center for Research and Education Kevin.Buterbaugh at vanderbilt.edu - (615)875-9633 _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20181004/dfc03e71/attachment.html>