On Wed, 2 Feb 2011, Gordan Bobic wrote:
> gordon is right about the SD/MMC card thing, but the
"level 10" ones
> can at least guarantee above 10mbytes/sec *read* capability. so
> _yes_ to the SATA interface.
The 10MB/s is _supposed_ to be for worst-case sequential writes. There
is, however, no defined benchmark, and manufacturers are free to do
their own testing. Most fail any sane real-world measurements of the
Just about every SD card I have seen apart from high end Lexar and
SanDisk manage a whopping 1-3 4KB write IOPS. Team Class 10 32GB SD card
is among those. So the class rating is pretty much completely
meaningless for anything except (at most) digital camera use where you
are sequentially writing large files to a FAT32 file system.
I'd suggest you have a look at the work being done by Arnd Bergmann on a
new device mapper target to overcome typical SD card misbehavior:
This is based on a survey of card behavior analysis compiled here: