Re: Need help with 8.4 Performance Testing - Mailing list pgsql-performance

From Matthew Wakeling
Subject Re: Need help with 8.4 Performance Testing
Date
Msg-id alpine.DEB.1.10.0812101338490.4666@aragorn.flymine.org
Whole thread Raw
In response to Re: Need help with 8.4 Performance Testing  (Scott Carey <scott@richrelevance.com>)
List pgsql-performance
On Tue, 9 Dec 2008, Scott Carey wrote:
> For what it is worth, you can roughly double to triple the iops of an Intel X-25M on pure random reads if you queue
up
> multiple concurrent reads rather than serialize them.  But it is not due to spindles, it is due to the latency of the
> SATA interface and the ability of the controller chip to issue reads to flash devices on different banks concurrently
> to some extent.  

Spindles, banks. What's the difference? The fact is that you have multiple
"things", and queuing up requests in the controller means that more than
one at a time can be active. The X-25M is basically a RAID controller in
its own right, connected to ten flash devices.

Matthew

--
 Don't worry!  The world can't end today because it's already tomorrow
 in Australia.

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