[gpfsug-discuss] FYI, Spectrum Scale 5.0.1 is out -NSD Checksum

Daniel Kidger daniel.kidger at uk.ibm.com
Fri May 11 20:02:30 BST 2018


>From some graphs I have seen the overhead varies a lot depending on the I/O size and if read or write and if random IO or not.
So definitely YMMV.

Remember too that ESS uses powerful processors in order to do the erasure coding and hence has performance to do checksums too. Traditionally ordinary NSD servers are merely ‘routers’ and as such are often using low spec cpus which may not be fast enough for the extra load?

Daniel


 

 
 	
Dr Daniel Kidger 
IBM Technical Sales Specialist
Software Defined Solution Sales

+ 44-(0)7818 522 266 
daniel.kidger at uk.ibm.com

> On 11 May 2018, at 19:34, Oesterlin, Robert <Robert.Oesterlin at nuance.com> wrote:
> 
> Ah be careful! looking at the man page for mmchconfig “nsdCksumTraditional:
>  
> https://www.ibm.com/support/knowledgecenter/STXKQY_5.0.1/com.ibm.spectrum.scale.v5r01.doc/bl1adm_mmchconfig.htm
>  
> Enabling this feature can result in significant I/O performance degradation and a considerable increase in CPU usage.
>  
>  
> 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: Friday, May 11, 2018 at 1:29 PM
> To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
> Subject: [EXTERNAL] Re: [gpfsug-discuss] FYI, Spectrum Scale 5.0.1 is out
>  
> On the other hand, we are very excited by this (from the README):
>         File systems: Traditional NSD nodes and servers can use checksums
>  
>             NSD clients and servers that are configured with IBM Spectrum Scale can use checksums 
>  
>             to verify data integrity and detect network corruption of file data that the client 
>  
>             reads from or writes to the NSD server. For more information, see the 
>  
>             nsdCksumTraditional and nsdDumpBuffersOnCksumError attributes in the topic mmchconfig command.
>  
> Finally!  Thanks, IBM (seriously)…
>  
> Kevin
> 
> 
> On May 11, 2018, at 12:11 PM, Sanchez, Paul <Paul.Sanchez at deshaw.com> wrote:
>  
> I’d normally be excited by this, since we do aggressively apply GPFS upgrades.  But it’s worth noting that no released version of Scale works with the latest RHEL7 kernel yet (anything >= 3.10.0-780). So if you’re also in the habit of aggressively upgrading RedHat then you’re going to have to wait for 5.0.1-1 before you can resume that practice.
>  
> From: gpfsug-discuss-bounces at spectrumscale.org <gpfsug-discuss-bounces at spectrumscale.org> On Behalf Of Bryan Banister
> Sent: Friday, May 11, 2018 12:25 PM
> To: gpfsug main discussion list (gpfsug-discuss at spectrumscale.org) <gpfsug-discuss at spectrumscale.org>
> Subject: [gpfsug-discuss] FYI, Spectrum Scale 5.0.1 is out
>  
> It’s on fix central, https://www-945.ibm.com/support/fixcentral
>  
> Cheers,
> -Bryan
>  
> 
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