[gpfsug-discuss] mmdiag --iohist question

IBM Spectrum Scale scale at us.ibm.com
Mon Jul 23 07:51:54 BST 2018


Hi

Please check the IO type before examining the IP address for the output of
mmdiag --iohist. For the "lcl"(local) IO, the IP address is not necessary
and we don't show it. Please check whether this is your case.

=== mmdiag: iohist ===

I/O history:

 I/O start time RW    Buf type disk:sectorNum     nSec  time ms  Type
Device/NSD ID        NSD node
--------------- -- ----------- ----------------- -----  -------  ----
------------------ ---------------
01:14:08.450177  R       inode    6:189513568        8    4.920   srv dm-4
192.168.116.92
01:14:08.450448  R       inode    6:189513664        8    4.968   srv dm-4
192.168.116.92
01:14:08.475689  R       inode    6:189428264        8    0.230   srv dm-4
192.168.116.92
01:14:08.983587  W     logData    4:30686784         8    0.216   lcl dm-0
01:14:08.983601  W     logData    3:25468480         8    0.197   lcl dm-8
01:14:08.983961  W       inode    2:188808504        8    0.142   lcl dm-11
01:14:08.984144  W       inode    1:188808504        8    0.134   lcl dm-7




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From:	"Buterbaugh, Kevin L" <Kevin.Buterbaugh at Vanderbilt.Edu>
To:	gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date:	07/11/2018 10:34 PM
Subject:	[gpfsug-discuss] mmdiag --iohist question
Sent by:	gpfsug-discuss-bounces at spectrumscale.org



Hi All,

Quick question about “mmdiag —iohist” that is not documented in the man
page … what does it mean if the client IP address field is blank?  That the
NSD server itself issued the I/O?  Or ???

This only happens occasionally … and the way I discovered it was that our
Python script that takes “mmdiag —iohist” output, looks up the client IP
for any waits above the threshold, converts that to a hostname, and queries
SLURM for whose jobs are on that client started occasionally throwing an
exception … and when I started looking at the “mmdiag —iohist” output
itself I do see times when there is no client IP address listed for a I/O
wait.

Thanks…

Kevin

—
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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