Re: Testing Sandforce SSD

Yeb Havinga wrote:
> Small IO size: 4 KB
> Maximum Small IOPS=86883 @ Small=8 and Large=0
>
> Small IO size: 8 KB
> Maximum Small IOPS=48798 @ Small=11 and Large=0

Conclusion:  you can write 4KB blocks almost twice as fast as 8KB ones.
This is a useful observation about the effectiveness of the write cache
on the unit, but not really a surprise.  On ideal hardware performance
should double if you halve the write size.  I already wagered the
difference in pgbench results is caused by the same math.

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Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us