Re: [linux-lvm] Software raid on top of lvm logical volume

[Theo Van Dinter <felicity@kluge.net>]

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On Thu, Oct 28, 2004 at 02:54:24PM -0400, Michael T. Babcock wrote:
> >You'd usually want to make your raid devices first, then put LVM on
> >top of it.  I can't really think of any benefits of doing it the other
> >way around.
> 
> I've thought about this numerous times -- there is the distinct resizing 
> advantage.  Namely, if I create a software RAID partition, I can't 
> resize it afterward without destroying it.  I have for example, on 

There's no resizing advantage at all -- if you add another disk to the LVM,
you can just as easily add it to a RAID array instead.

Never mind the fact that if you lose any disk in the LVM, your RAID groups are
dead (unless you split up your LVM disk, but that's what RAID does ...)

LVM gives you flexibility in your disk layout, RAID gives you performance
+ reliability.  LVM builds on RAID's features, but the other way around,
RAID is undercut by LVM.

> I understand this may not be optimal in some situations, but some of us 
> don't have thousands of dollars for SCSI HW RAID controllers.

Neither do I, but this is irrelevent to the conversation.

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