Re: raidctl -B syntax

[Greg Oster <oster%cs.usask.ca@localhost>]

On Mon, 21 Dec 2015 00:25:02 +1100
matthew green <mrg%eterna.com.au@localhost> wrote:

> > I am confident that an I/O error duing reconstruction will result
> > in the reconstruction failing.
> 
> it does for RAID1.  i've not used RAID5 for years.

It does for RAID 5 as well.

> i had a disk failure, followed by the otherside giving read
> errors while reconstructing.  my rebuild failed sort of
> appropriately (it would be nice if the re-rebuild would know
> where to restart from.)
> 
> (i managed to recover the failed blocks from the 2nd disk
> from the 1st one.  at least they managed to fail in different
> regions of the dis, obviating the need for more annoying
> methods of restore :-)

About a year ago I had to build a custom kernel to ignore IO errors on
the source disk...  A RAID 1 set had failed the second component, and
it turned out the first component also had read errors.  Fortunately,
the blocks with errors were not associated with any filesystem bits (a
full dump, for example, worked fine) and so I was able to recover
everything without having to go to backups. (i.e. custom kernel
recovered bits to new second component, and then the first component
got replaced as well!)

Later...

Greg Oster