[mythtv-users] SSD disk for DB
Jay Ashworth
jra at baylink.com
Tue Oct 9 03:10:01 UTC 2012
----- Original Message -----
> From: "Gary Buhrmaster" <gary.buhrmaster at gmail.com>
> On Mon, Oct 8, 2012 at 7:08 PM, jedi <jedi at mishnet.org> wrote:
> ....
> > SSD's are great for random IO which is what you tend to hit hard
> > with
> > most databases.
>
> Random *read* I/O (because the seek time is closer to zero).
> Whether they are great for *write* I/O depends on their designs
> (the seek time is still closer to zero, but (re)writing blocks
> may take some time in some designs, and databases tend
> to insist on durable writes (data committed to "disk") in order
> to insure ACID compliance). As with much else, your mileage
> will vary.
Note too that you have to *know that your device isn't lying to you
about whether it's written the data*; this is often more information than
you can get without (sometimes destructive) testing, from consumer component
vendors. And we already know that Flash SSD controller manufacturers
lie about some things (though I'm damned if I remember what; bit the
Linux driver people a couple years ago).
Cheers,
-- jra
--
Jay R. Ashworth Baylink jra at baylink.com
Designer The Things I Think RFC 2100
Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII
St Petersburg FL USA #natog +1 727 647 1274
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