Raid1 failure rules?

Nancy Sollars plug-discuss@lists.PLUG.phoenix.az.us
Fri, 21 Dec 2001 14:53:16 -0700


from reading the software raid and the raid info on the e-smith site ...

It looks as though if the drive fails ( for what ever reason ) .. its
ignored they dont mentaion anything about re-attempting to read ot to write
to the fail'd device ..

Nige
----- Original Message -----
From: <alandd@mindspring.com>
To: <plug-discuss@lists.PLUG.phoenix.az.us>
Sent: Friday, December 21, 2001 2:19 PM
Subject: Raid1 failure rules?


> I asked this question on the linux-raid email list and absolutely no one
responded to it.  I am not that surpised since of all the RAID info out
there, the nuts and bolts rules are seemingly not discussed by anyone (at
least not for free).
>
> So, I come to PLUG where many questions are answered or at least responded
to.  Anyone have any ideas on where to get info on the subject, other than
reading the source (most accurate but most time consuming)?
>
> Alan
>
> --<original post to linux-raid below>--
>
> Date:     2001-12-19 17:16:04
>
> Hello,
>
> As I am investigating software RAID1 operation in Linux, I am finding more
questions after I find my initial answers.  Specifically, I am wondering
about mirror failure rules.  For example:
>
> If the read from one mirrored drive fails, the data is taken from the
other drive.  Fine.  But, is the drive that failed the read that one time
now declared entirely bad or does the RAID code attempt to recover that bad
sector by re-writing the data from the good drive?  Or, is there some
threshold number for read errors from a drive that must be reached before it
is declared as bad?  What about write errors?
>
> I guess I want to know exactly what errors and what rules regarding errors
must be met for a mirrored drive to be marked bad.  Is there a reference or
resource somewhere, industry standard or otherwise, that defines this?  Even
just a pointer to the source code that makes these decisions would be fine.
>
> Alan
>
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