Re: Very slow transfers to/from micro SD card on a RPi B+

[Michael <macallan%netbsd.org@localhost>]

Hello,

On Thu, 9 Jul 2015 11:28:17 +0200
Jean-Baka Domelevo Entfellner <domelevo%gmail.com@localhost> wrote:

> Hi there,
> 
> I'm currently untarring a pkgsrc.tar.gz (48MB) to /usr. The
> commandline I used is:
> # nohup tar xfz pkgsrc.tar.gz -C /usr &
...
> It's on average between 0.20 and 0.25 MB/s, don't you think it's
> unreasonably slow? Do you have any piece of advice for me?

It should write at least 1MB/s. Is the partition you're writing to
aligned to something like 16MB? Really odd alignments ( like, less than
a filesystem block ) will force the card to do lots and lots of
read-modify-write cycles which will slow it to a crawl.

have fun
Michael