Ext3 users - Feb 2010 - Is my data checksummed?

What checksumming is done for the actual data?  I know that storage 
devices often do their own checksumming too, but how can I be sure my 
data is integrity checked every time I read it?

PS:
ext2/ext4?

Thank you very much.

Reza.

On Fri, 19 Feb 2010 at 20:15, Reza Roboubi wrote:
> What checksumming is done for the actual data?
Ext4 introduced journal checksumming[0], but not for the actual data. 
Ext2/3 don't have checksums at all, IIRC.
> often do their own checksumming too, but how can I be sure my data is
> integrity checked every time I read it?
Btrfs has data checksumming :-)

Christian.

[0] http://ext4.wiki.kernel.org/index.php/Ext4_Howto#Journal_checksumming
-- 
BOFH excuse #144:

Too few computrons available.

On Fri, Feb 19, 2010 at 08:15:30PM -0800, Reza Roboubi
wrote:
> What checksumming is done for the actual data?  I know that storage
> devices often do their own checksumming too, but how can I be sure
> my data is integrity checked every time I read it?
If you use disks that support the Data Integrity Field (DIF)
extension, Linux will use it to provide end-to-end data checksum
support.  Otherwise, there are checksums on the disk and between disk
controller and the CPU, but those are obviously not end-to-end
checksums.

Adding data-level checksums is not something that we are planning on
adding to the ext2/3/4 file systems.  BTRFS is the only file system
that has data-level checksums, but it's not yet production ready.

Best regards,

					- Ted