Production databases on SSDs?

[Dave Hodgkinson]

On 10 Nov 2009, at 20:36, Dirk Koopman wrote:

> Ovid wrote:
>> Does anyone here have any experience putting a production database  
>> on a solid-state drive?  Our database is heavily used and it sounds  
>> to me like we could get a massive performance boost for minimal  
>> cost and no architectural changes.  Are there any downsides I  
>> should be aware of?
>
> Write cycles. They are very limited.
>
> Even on best kwalitee flash chips you will only get approx 100,000  
> write cycles. Most flash controllers "get over" this by doing "wear  
> levelling"  (which means that writes are spread about the available  
> blocks and not concentrated on the same few blocks [think inodes]).  
> This will get you another couple of orders of magnitude. So maybe  
> 10,000,000 write cycles.
>
> Then there is the UDI file system. Which does some other  
> optimisations, but is probably no (or not much) better than the wear  
> leveling hardware.
>
> Heavy usage? Don't think flash will help you, or at least - not for  
> long.
>

I'm kinda concerned that this is all trying to sidestep understanding
of database usage. It slapping 32G of RAM on top of a hard drive
really not good enough? Do you really not have control over the
database queries?



-- 
Dave Hodgkinson                                MSN: davehodg at hotmail.com
Site: http://www.davehodgkinson.com                  UK: +44 7768 490620
Blog: http://www.davehodgkinson.com/blog
Photos: http://www.flickr.com/photos/davehodg