Re: Lun size and performance with flash disks : rh7

Hello Thierry,
first counter question for storage vendor would be: Can you please provide a benchmark (with raw data if possible) that proves your statement?

I mean it is always important to check what they are referring/comparing to. Comparing one SSD/Flash LUN to some old rusty spindle disks ... well yes ... in this case SSD/Flash might always be faster and you are happy anyway.

However if you compare one SSD LUN vs. ten SSD LVM striped LUNs with +15K IOPS or so ... well then the picture is different.

This topic is pretty easy to verify. Just run your workload (e.g. SLOB benchmark) on a file system backed by one big SSD LVM LUN and on file system backed by ten striped LVM SSD LUNs and monitor with iostat -xk 1 <LUNs> .... you gonna see the difference for sure.

Based on my experience with a lot of performance benchmarks - multiple striped (SSD) LUNs make an impact on systems with big I/O load :-)

Best Regards
Stefan Koehler

Independent Oracle performance consultant and researcher Website: http://www.soocs.de
Twitter: _at_OracleSK

> thierry gascard <tgascard_at_gmail.com> hat am 25. Juni 2020 um 08:51 geschrieben:
>
> Hello ,Storage vendors claim that we do not care anymore about io queue per lun on scsi.Two years ago I made test on ssd , and have multiple luns on data rather than a big one improve performance. Does anyone have feedback about it ?

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