[gpfsug-discuss] Long I/O's on client but not on NSD server(s)

[Frederick Stock]

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


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