Corrupted files

[Sean Caron]

Hey, just sharing some hard-won (believe me) professional experience. I
have seen xfs_repair take a bad situation and make it worse many times. I
don't know that a filesystem fuzzer or any other simulation can ever
provide true simulation of users absolutely pounding the tar out of a
system. There seems to be a real disconnect between what developers are
able to test and observe directly, and what happens in the production
environment in a very high-throughput environment.

Best,

Sean


On Tue, Sep 9, 2014 at 6:24 PM, Eric Sandeen <sandeen at sandeen.net> wrote:

> On 9/9/14 11:03 AM, Sean Caron wrote:
>
>  Barring rare cases, xfs_repair is bad juju.
>>
>
> No, it's not.  It is the appropriate tool to use for filesystem repair.
>
> But it is not the appropriate tool for recovery from mangled storage.
>
> I've actually been running a filesystem fuzzer over xfs images, randomly
> corrupting data and testing repair, 1000s of times over.  It does
> remarkably well.
>
> If you scramble your raid, which means your block device is no longer
> an xfs filesystem, but is instead a random tangle of bits and pieces of
> other things, of course xfs_repair won't do well, but it's not the right
> tool for the job at that stage.
>
> -Eric
>
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