[Sugar-devel] Filesystem for SD cards / USB sticks (was: Re: Unbootable machine)

[Jonas Smedegaard]

On Mon, Aug 31, 2009 at 10:41:50AM +0200, Sascha Silbe wrote:
>On Sun, Aug 30, 2009 at 09:33:22PM -0400, Bernie Innocenti wrote:
>
>>On a side note, which filesystem should be chosen in order to minimize
>>wearing to USB sticks?
>Only the manufacturer can know. Maybe we should ask a few of them. :-|
>The problem is that the FTL is highly proprietary and very likely 
>tuned to the FAT filesystem (since it's the one mandated by the SD 
>card standard).

SD card standard?!?

I believe USB sticks (as was asked about) are not bound by the SD card 
standard.

You are still right about SD (including SDHD) cards, though.

And you are still right that we no nothing about the prorietary 
internals of FTS (or similar, in case that term is tied to SD).


>>I would assume that the any DOS filesystem will continouously rewrite 
>>to the FAT blocks.  Maybe the best choice would be ext4 with the 
>>journal disabled?
>The increase of data written to the card with journalling enabled is 
>less than 4% for normal operations (up to 42% for very 
>metadata-intensive operations, but then the amount written is low in 
>absolute terms) according to Ted Ts'o [1] (who has quite a number of 
>interesting SSD-related articles in his blog). For me having a 
>journalling filesystem is worth a lot more than just 4% write data 
>increase (I even use data=journal on most systems).

I know that article, and the reason I still recommend disabling 
journaling is due to that "write amplification effect" also mentioned in 
the article.

So do you do not care about the write amplification effect, or so you 
assume that SD card and USB sticks have silently solved it similarly to 
the (seemingly high-end) Intel X25-M SSD?


Kind regards,

  - Jonas

-- 
* Jonas Smedegaard - idealist & Internet-arkitekt
* Tlf.: +45 40843136  Website: http://dr.jones.dk/

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