On Wed, Apr 22, 2015 at 12:18 PM, David Pacheco <[email protected]> wrote:

> We have a number of storage pools that report "16.0E" for the "freeing"
> property.  Using "-p" to get a more precise number, we have values like
> these:
>
>     18446744072282297939
>     18446744073709544128
>     18446744073709549120
>
> or, as signed 64-bit values:
>
>     -1427253677
>                 -7488
>                 -2496
>
> Have others seen this?
>

I haven't.


> Given that this seems to indicate that we've freed more data than we
> expected to, could this be indicative of corruption?
>

I'd say these values being wrong is "corruption" by itself (albeit mostly
harmless), but it could also be indicative of a larger problem.


> In case it's relevant: most of the affected systems were previously
> affected by spacemap corruption related to async destroy[1].
>

That could definitely cause this -- if we free the same block twice, you'd
get the spacemap corruption, and also the "freeing" would be decremented
twice for the same block, causing it to eventually go negative.


> But the system with the largest negative value was installed recently and
> has only ever run bits as new as February.[2]
>

I don't know what would cause that.  The first step to tracking this down
would probably be to determine whether it's due to background free of
filesystems/zvols vs snapshots.

--matt


>
> Thanks,
> Dave
>
> [1] https://www.illumos.org/issues/4504
> [2] To be precise:
> https://github.com/joyent/illumos-joyent/tree/e1f322da435434b3a1f9c091e431efae6816ae4c
> .
>
>
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