Re: [linux-lvm] LVM2 seems to chop performance by 33%

[David Greaves <david dgreaves com>]

Alasdair G Kergon wrote:

> On Sun, Jun 20, 2004 at 07:17:58PM +0100, David Greaves wrote:
>  
>
> > No-one ever replied as to why blockdev --setra / --getra is not the same 
> > as that displayed in lvdisplay
> > And it's not documented that I can find. There's a comment: "Not used by 
> > device-mapper." And that means.....?
> >    
>
> Any LVM read ahead setting is ignored by LVM2 i.e. not passed to the kernel.
>
> If it's demonstrated to be useful it could still be implemented, but
> the current development priorities are still correctness and new features 
> rather than performance.
>
> Alasdair
>  
Thanks Alasdair

It would be good to modify the docs to be clearer and maybe say "use 
blockdev --setra"

David