Analysis of disk file block with ZFS checksum error
Joe Peterson
joe at skyrush.com
Fri Feb 8 22:58:15 UTC 2008
Mark Day wrote:
> Based on the subset of data you posted, the bad data looks like ASCII
> text.
> The bad data from offset a0000 to a000f is:
>
> ${138AFE{@
> @$$}1
>
> The bad data from offset af6c1 to af6c8 is:
>
> 392A9}@
>
> I don't recognize the content beyond that, but I'd guess that somehow
> the
> contents of some other file managed to overwrite that portion of the bad
> file. As for how that happened, I don't know. But if someone
> recognizes
> where the bad content came from, that might be a clue.
Gary/Mark,
Good eye! Yes, it indeed does appear to be ASCII. I *thought*
something in the repetition when I originally did an od -a looked
interesting.
I dumped the whole bad section as a string, and here's (partly) what I get:
${138AFE{@
@$$}138AFE}@
@$${138AFF{@
[A3:^80(^91^2146F)]
@$$}138AFF}@
@$${138B00{@
@$$}138B00}@
@$${138B01{@
[181:^80(^91^2146F)]
@$$}138B01}@
@$${138B02{@
@$$}138B02}@
@$${138B03{@
[2C:^80(^91^2146F)]
@$$}138B03}@
@$${138B04{@
@$$}138B04}@
.
.
.
@$${138B8B{@
<(21470=Thu Jan 24 23:20:58 2008)>
[117:^80(^91^21470)]
@$$}138B8B}@
.
.
.
@$${138C18{@
<(21472=1201242069)>[-2:^80(^82^85)(^83^1B5)(^84=b)(^85=1)(^86=0)(^87=0)
(^88=0)(^89^2146C)(^8A=)(^8B=40)(^8C=2e)(^8D^84)(^8E=0)(^90^21472)
(^91^21460)]
@$$}138C18}@
@$${138C19{@
<(21473=a72f78)>[2:^80(^89^21473)]
@$$}138C19}@
@$${138C1A{@
@$$}138C1A}@
.
.
.
and more of the same. Note the date string. There are several like
that. Anyone recognize this text format?
-Joe
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