Re: RAID-6 support in kernel?

["Jakob Østergaard" <jakob@unthought.net>]

On Wed, Jun 05, 2002 at 09:57:01AM +0200, Luca Berra wrote:
> On Tue, Jun 04, 2002 at 10:20:53PM +0200, Jakob Østergaard wrote:
> > What often happens (in my experience) is, that a number of disks build up bad
> > blocks.  One day, you hit one of those bad blocks, and that one disk is kicked
> > from the array.
> > 
> > When you re-sync, you *will* hit the remaining bad blocks on the other disks,
> > causing the array to fail completely.
> > 
> > Using hot-spares will "automate" this failure - meaning that an administrator
> > may not be anywhere near the system when this total failure happens.
> > 
> > Not using hot-spares is less "automatic" in the lucky case where everything
> > works, but it also assures that an administrator actually is near the system
> > when the total failure is likely to occur.
> well, what we could do to prevent this. if you don't have or trust S.M.A.R.T.

I have and use SMART, and because of my experiences with it I do not trust it  :)

> is having a 'consistency check' function in md, that would read from all disks
> and even compare data or calculate parity for raid5, it could be scheduled
> to run periodically with a very very low priority.

This definitely belongs in user-space.  But you are right, and I've discussed
it with colleagues before as well - it would be a good thing to have such a
tool.

In root's crontab you could easily just put a 'dd if=/dev/hda of=/dev/null' and
so on for all your drives.   No need for kernel extensions here...

-- 
................................................................
:   jakob@unthought.net   : And I see the elder races,         :
:.........................: putrid forms of man                :
:   Jakob Østergaard      : See him rise and claim the earth,  :
:        OZ9ABN           : his downfall is at hand.           :
:.........................:............{Konkhra}...............:
-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html