Re: Linux Buffer Cache Does Not Support Mirroring

Gerard Roudier (groudier@club-internet.fr)
Sun, 31 Oct 1999 13:52:44 +0100 (MET)


On Sat, 30 Oct 1999, Pavel Machek wrote:

> Hi!
>
> > Which is exactly what we have concluded. We probably should provide
> > some input into 2.5 for our needs. We would be happy to put in the
> > subsystems we require. The benefit to Linux would be a built in fault
> > tolerant redirector within the cache (which is useful for this and
> > distributed support -- time to start thinking about this). This would
> > allow all of the Linux file systems to support multi-segmented
> > mirroring and fault tolerant failover without the RAID drivers.
>
> What is problem with the RAID drivers?

Could I try a couple of guesses?

Guess number 1:
---------------
In my opinion, some commercial company only wanted to implement mirroring
and so they didn't make the effort to design and implement RAID as a
generic kernel feature where mirroring is just a profile for this RAID
facility. It might well have happended they did the thing at the kernel
place it was easiest for them to implement it.
Result might be that they now have to deal with some legacy that
unfortunately donnot accomodate the layering of Linux RAID design and
implementation.

Guess number 2:
---------------
Someone just missed that Linux has support for mirroring. ;-)

Gérard.

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