Re: Where to put RAID (was Re: LVM etc... biggest thread in history)

Heinz Mauelshagen (mauelsha@ez-darmstadt.telekom.de)
Mon, 17 Aug 1998 14:49:36 METDST


On 17 Aug 1998 Shawn Leas wrote:

> LVM is a physical to logical address remapping mechanism, that will do
> software RAID, in which case there is an interface by which you can get
> info about any given metadevice (LV). For instance, if you want to know
> about the RAID personality of an LV, there are lv_ functions that will
> give you this in the liblvm.
>
> As for separating RAID and LVM, this is a fundamental mistake IMHO,
> because you are duplicating the most basic functionality of the LVM in the
> RAID code, which is the physical to logical address remapping. It is the
> foundation on which both principals are built! If ANY separation is to be
> done, it would be making the remapping mechanism totally generic, and
> building both RAID LVM modules on top of that, and that is just being
> anal. (That is just my opinion, the rest should be fact)
>
> LVM is therefore the best place to put RAID, as RAID is just an LV
> personality, so to speak.

I share Shawns point of view.

BTW: the use of MD is supported by LVM at this point in time to have the
advantages of RAID > 0 by using MDs before LVM itself will integrate
these RAID levels.

<SNIP>
> I say, learn from Veritas.

That's it.

Heinz

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