[Twg] [Discuss] T10 End-to-End Data Integrity HLD

[Andreas Dilger]

There is actually work well underway to add metadata checksums for ext4 into the upstream kernel.

This is using both inline and out-of-band locations to store the block checksum for the different metadata block types. The checksums on disk are crc32c. 

Cheers, Andreas

On 2012-04-24, at 14:03, Johann Lombardi <johann at whamcloud.com> wrote:

> On Sun, Apr 22, 2012 at 5:36 AM, Alexey Lyashkov <alexey_lyashkov at xyratex.com> wrote:
> Why not? HCA provide a T10 checksumming when obdfilter (osd) submit a IO request - so it's before a call bio_done() function and before send a reply to client.
>  
> so we may don't want a commit as HCA verify a checksum and it's correct.
> 
> I was actually concerned by checksum errors when committing metadata blocks to disk. That said, i assume that the low level driver is supposed to resubmit the I/O several times (ideally via multipath) on checksum errors and ultimately triggers a failover (to replay the I/O), right?
> 
> Cheers,
> Johann
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