Re: which kernel do people use?

[John R Pierce <pierce@xxxxxxxxxxxx>]

On 10/24/2013 4:12 PM, Lists wrote:
> Going from HDD to SSD's gave us better than a 95% reduction in query
> times for complex queries using PostgreSQL on otherwise identical
> hardware. I wouldn't have believed it had I not seen it directly, for
> myself.

in some tests I ran, also using postgresql, a raid10 of 20 15000 rpm 
SAS2 hard drives performed about as fast as a raid0 of 4 SAS2 enterprise 
SSD's at a very write intensive highly concurrent OLTP style (many small 
updates) workload.   both storage arrays were behind a HP SmartArray 
controller that had a 2GB write cache (with supercap/flash backup)

when I exercised the SSDs for a week continuously such that their full 
capacity had been written several times over, they slowed down 2 or 3 to 
1 from their original speed.  at no point was the SSD array more than 
50% full.

-- 
john r pierce                                      37N 122W
somewhere on the middle of the left coast

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