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<div dir="ltr"><span><span style="caret-color: rgb(62, 62, 62); color: rgb(62, 62, 62); font-family: UICTFontTextStyleBody; font-size: 17px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); -webkit-text-size-adjust: none; -webkit-text-stroke-width: 0px; text-decoration: none; display: inline !important; float: none;">I’m
guessing IBM doesn’t generally spend huge amounts of money on things that are superfluous...although *cough*RedHat*cough*. </span></span>
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<div dir="ltr">TCP does of course perform checksumming, but I see the NSD checksums as being at a higher “layer”, if you will. The layer at which I believe the NSD checksums operate sits above the complex spaghetti monster of queues, buffers, state machines,
kernel/user space communication inside of GPFS as well as networking drivers that can suck (looking at you Intel, Mellanox), and high speed networking hardware all of which I’ve seen cause data corruption (even though the data on the wire was in some cases
checksummed correctly).
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<div dir="ltr">-Aaron </div>
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<div class="null" dir="auto">On October 30, 2018 at 05:03:26 EDT, Jonathan Buzzard <jonathan.buzzard@strath.ac.uk> wrote:<br class="null">
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<div nop="PlainText" class="null">On 29/10/2018 20:47, Stephen Ulmer wrote:<br class="null">
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[SNIP]<br class="null">
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> <br class="null">
> If ESS checksumming doesn’t protect on the wire I’d say that marketing <br class="null">
> has run amok, because that has *definitely* been implied in meetings for <br class="null">
> which I’ve been present. In fact, when asked if Spectrum Scale provides <br class="null">
> checksumming for data in-flight, IBM sales has used it as an ESS up-sell <br class="null">
> opportunity.<br class="null">
> <br class="null">
Noting that on a TCP/IP network anything passing over a TCP connection <br class="null">
is checksummed at the network layer. Consequently any addition <br class="null">
checksumming is basically superfluous.<br class="null">
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JAB.<br class="null">
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-- <br class="null">
Jonathan A. Buzzard Tel: +44141-5483420<br class="null">
HPC System Administrator, ARCHIE-WeSt.<br class="null">
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG<br class="null">
_______________________________________________<br class="null">
gpfsug-discuss mailing list<br class="null">
gpfsug-discuss at spectrumscale.org<br class="null">
<a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_BLANK" class="null">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a><br class="null">
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