which file system for sd card?

Pietro "m0nt0" Montorfano monto84 at gmail.com
Sun Jan 25 17:56:26 CET 2009

Fernando Martins ha scritto:
> Pietro "m0nt0" Montorfano wrote:
>> William Kenworthy ha scritto:
>>> I found vfat clearly better (less susceptible to corruption) than ext2,
>>> however ext3 is better than vfat, but will still play up at times.
>>> Using it for OSM maps
>>> BillK
>> IMHO the best fs for sd is vfat if you don't care about permission, so 
>> if you have to put your photos or docs on it, else ext2 is BETTER than 
>> ext3 in this case for a simple reason, it doesn't have the journal.
>> Not having the journal imlies a redouced number of write to sd and a 
>> reduced probability to get the data lost.

My point is: journal could avoid errors and prevent some corruption, ok 
nothing to say about that. BUT if the journal is on the same partition 
of the sd (and of course usually is like that), and the partition 
becomes unusable you loose journal and fs, so, no benefit from journal.
If the kernel is writing to journal META-DATA (yeah, meta data not the 
real data) it's not writing the datas, if it's writing the data, the 
journal is not up to date. These additional writes given by the journal 
gives an extra possibility to loose the data and make the fs slow.
Last but not least argument is that if you loose some data you can have 
a journal giving you the right logical data reconstruction but it can 
occur that a file is logically well represented but the data of the file 
are in some manner lost or corrupted.
So, if my argumentation are not totally wrong, ext2 is better than ext3 
in sd card if the comparison is between ext2, ext3 and FAT.



P.S. obviously IMHO

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