[Beowulf] Big storage

Andrew Walrond andrew at walrond.org
Thu Aug 30 02:31:01 PDT 2007

Bruce Allen wrote:
> Yes, precisely.
> When I buy RAID controllers, I put this requirement directly in my bid
> specifications.  I say something like the following:
> ------------------------------------------------------------------
> During a READ operation, if the RAID controller finds an unreadable
> (uncorrectable) disk sector, then it will immediately reconstruct the
> missing data for that sector using redundant data from the rest of the
> array, and WRITE that data to the unreadable (uncorrectable) sector to
> force sector reallocation if needed by the disk.
> In addition, the RAID controller will perform a continous or regular (at
> least daily) background scan of all disk sectors to identify and repair
> any unreadable sectors as described above.
> ------------------------------------------------------------------
> I think it is a mistake to purchase a RAID controller without these
> features.  The absence of these features is the main reason that I don't
> think Linux software RAID is very good.

Ouch! I'd mentally filed linux software raid and good and trustworthy
quite a while ago and use it heavily. Presumably the maintainers (Neil
Brown? or is he just the mdadm maintainer) are aware of this lack/criticism?

As presented, it certainly seems like features that ought to be added.
It would be interesting to cc LKML for comment.

Andrew Walrond

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