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

[Jean-Baka Domelevo Entfellner <domelevo%gmail.com@localhost>]

On Sat, Jul 18, 2015 at 10:38 AM, Reinoud Zandijk <reinoud%netbsd.org@localhost> wrote:
> Hi,
>
> On Thu, Jul 09, 2015 at 11:53:26AM -0400, Michael wrote:
>> On Thu, 9 Jul 2015 11:28:17 +0200 Jean-Baka Domelevo Entfellner
>> <domelevo%gmail.com@localhost> wrote:
>> > 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.
>
> This is a common issue with most file systems indeed. I'd advise to use WAPBL
> (-olog) or even async (-oasync). Esp. async ought to be a lot faster.
>

Thanks, but what is the route to follow in order to activate WAPBL? Do
I have to recompile the kernel?
I am using the regular NetBSD archives from the NetBSD FTP...

Thanks,
    JB