Stress testing the UFS2 filesystem

Peter Holm peter at holm.cc
Wed May 3 07:54:53 UTC 2006


> On Wed, May 03, 2006 at 07:48:17AM +0200, Bj?rn K?nig wrote:
>> Kris Kennaway schrieb:
>> >On Wed, May 03, 2006 at 12:32:29AM +0400, Pavel Merdine wrote:
>> >>Of course I think we could do patches to overcome corrupting panics,
>> >>but the core FreeBSD team would not accept this, as they are happy
>> >>with panics and corruptions they make to other filesystems.
>> >
>> >Of course not, don't make silly accusations :-)
>> >
>> >The problem is much more difficult to solve than "making the panic an
>> >error return".
>>
>> I'm interested in more information about this issue. Do you have a
>> reference to an old discussion about this topic or do you like to
>> explain it a little bit further for me (and probably others)?
>
> See the URL that Peter provided in his original post.
>
> The issue that he is testing is how well the filesystem behaves when
> you arbitrarily damage it and then run fsck (ideally, fsck should
> detect all of the damage and repair it).  He seems to have found cases
> where fsck does not detect and repair the damage, leading to panics at
> runtime.
>

Actually the filesystems mounts without any problems if fsck is run first.

The objective of this exercise was to show that background fsck may lead
to panics. This was a problem I saw a lot a year ago when I did some
testing of patches and in the cause of a working day saw two or three
panics. With background fsck I would from time to time get a secondary
panic, which typically zapped the original crash dump.

- Peter

- Peter

> You can ignore Pavel's reply since he didn't have anything to add to
> the discussion :-)
>
> Kris
>


- Peter Holm


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