which file system for sd card - for Wiki
fernando at cmartins.nl
Sun Jan 25 23:35:16 CET 2009
arne anka wrote:
> if it is not yet in the wiki, somebody should probably gather the bits
> from the archives and put it there -- it seem to be a rather recurrent
I wrote the following text which I can put somewhere in the wiki. Since
I'm no authority on the matter, I would appreciate feedback from the
I got a new SD card. Which file system is the best?
In general, vfat or ext2 are the most recommended.
Vfat might already be the fs in your card when you got a new one. It has
the advantage of being recognised in many other systems. The data
structures are simpler which might mean less writes on the sd-card and
less code being executed (this statement should have some objective
verification) and you'll find more tools available to recover
information when you get errors.
ext is Linux centric but one of the most tested and tuned. It is also a
faster file system than vfat (citation?) and most importantly, if you
need, it supports permissions, which vfat doesn't.
What about file systems like jffs2 and ubifs, which are aware of flash
SD cards, according to SanDisk specs, should have wear leveling logic,
which controls the number of writes and remaps blocks as needed.
Wear-aware file systems might actually play against the logic of the
card are usually not recommendable.
What about journaled file systems like ext3?
The advantage is that it will maintain your data in a consistent state.
However, the journal uses extra space and will impose more writes in the
sd card, thus decreasing performance and wearing the card.
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