[gpfsug-discuss] What NSDs does a file have blocks on?

Oesterlin, Robert Robert.Oesterlin at nuance.com
Mon Jul 9 21:21:29 BST 2018


I don’t think you can do it directly, but you could probably use FileHeat to figure it out indirectly. Look at mmchconfig on how to set these:

fileHeatLossPercent 20
fileHeatPeriodMinutes 1440

Then you can run a fairly simple policy scan to dump out the file names and heat value, sort what’s the most active to the top. I’ve done this, and it can prove helpful:

define(DISPLAY_NULL,[CASE WHEN ($1) IS NULL THEN '_NULL_' ELSE varchar($1) END])

rule fh1 external list 'fh' exec ''
rule fh2 list 'fh' weight(FILE_HEAT) show( DISPLAY_NULL(FILE_HEAT) || '|' || varchar(file_size) )

Bob Oesterlin
Sr Principal Storage Engineer, Nuance


From: <gpfsug-discuss-bounces at spectrumscale.org> on behalf of "Buterbaugh, Kevin L" <Kevin.Buterbaugh at Vanderbilt.Edu>
Reply-To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date: Monday, July 9, 2018 at 3:04 PM
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Subject: [EXTERNAL] [gpfsug-discuss] What NSDs does a file have blocks on?

Hi All,

I am still working on my issue of the occasional high I/O wait times and that has raised another question … I know that I can run mmfileid to see what files have a block on a given NSD, but is there a way to do the opposite?  I.e. I want to know what NSDs a single file has its’ blocks on?  The mmlsattr command does not appear to show this information unless it’s got an undocumented option.  Thanks…

Kevin

—
Kevin Buterbaugh - Senior System Administrator
Vanderbilt University - Advanced Computing Center for Research and Education
Kevin.Buterbaugh at vanderbilt.edu<mailto:Kevin.Buterbaugh at vanderbilt.edu> - (615)875-9633




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