Multi threaded random IO

Multi threaded random IO

[Milind Dumbare]

Any standard comparison between multi threaded random Write vs multi 
threaded random Read on XFS or any other filesystem?

I see multi threaded random Write faster than multi threaded random 
Read. Which is contradictory to standard "Reads faster that Writes" law.

My test setup is.
10MB record size, 2TB filesize, 8 threads.iozone

Any comments?

Thanks,
Milind

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Re: Multi threaded random IO

[Emmanuel Florac]

Le Fri, 17 Jul 2009 02:28:14 -0700
Milind Dumbare <milind@gslab.com> écrivait:

> I see multi threaded random Write faster than multi threaded random 
> Read. Which is contradictory to standard "Reads faster that Writes"
> law.
> 
> My test setup is.
> 10MB record size, 2TB filesize, 8 threads.iozone
> 
> Any comments?

Well it very much depends upon your underlying hardware. For instance
3Ware RAID cards with default settings read very poorly, they even get
much slower in sequential read than sequential write.

So basically you have to provide much more detailed hardware setup :
storage hardware, attachment, number and type of drives, RAID level...

-- 
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Emmanuel Florac     |   Intellique
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