[mythtv-users] MySQL on SSD 99% Utilization

[Rob Smith]

On Thu, Feb 3, 2011 at 10:38 AM, Matthew McClement <mythtv at macker.co.uk> wrote:
> Eh? SSD's are significantly slower at writes than reads, especially if
> you're writing to a non-GC'd cell, which with how the Toshiba controller
> handles TRIM is entirely possible(GC isn't continuous but rather seems
> to be demand triggered). If you then add non-aligned sub-page sized
> writes, things can get bad pretty quickly.
>
> It's buffering and other tricks which make SSD's faster today over the
> early versions, rather than slower.
>
> And it's not like that result is an oddity. Just look at any benchmark
> for the early JMicron based SSDs to see SSDs that were often *slower*
> than hard disks at random writes.
>
> Matt

Those benchmarks do look incorrect. For example:
4KB Random Reads:
Kingston SSDNow V Series (30GB) - 9.1 MB/s
Western Digital VelociRaptor (600GB) - 68 MB/s

4KB Random Read (4K Aligned)
Kingston SSDNow V Series (30GB) - 9.4 MB/s
Western Digital VelociRaptor (600GB) - 68 MB/s
That is just wrong or a really really crappy SSD