File System Selection

Eric Sandeen sandeen at
Tue May 5 15:23:22 UTC 2009

Ramesh wrote:
> Hi All,
> I am developing a SD Block Driver.
> As per old specification (SD Spec 2.0 ) Maximum size of SD memory
> card is 32 GB. - We used ext2 file system.
> By referring the new Specification (SD Spec 3.0) SD memory card size
> is reached upto and including 2TB (Terra Byte) - Block size strictly
> limited to 512 only (as per specification).
> My Questions.
> 1. For 2TB disk with Block size 512, Which file system is preferred
> (ext3/ext4)

do you mean sector size of the block device, or block size of the
fileystem?  I guess it doesn't matter much either way, 2^32*512 is 2T.
Either ext3 or ext4 can handle this size, you'll probably need to make
your decision based on other factors.

> 2. In a 32 bit machine, If I installed the Fedora 10 ( having ext4),
> am I able to use it as effectively ( for the maximum disk/file size
> usage). To utilize 2TB or more size hard disk, is this allowable to
> use 32 bit machine with Ext4 fs?

On a 32 bit machine you will be limited to 16T, this is actually a page
cache limitation.  But 2T should be fine.


> Thanks in advance.
> Regards, Ramesh

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