[linux-lvm] Wierd lvm2 performance problems

[Eugene Vilensky]

Google brought up this bug
https://bugzilla.redhat.com/show_bug.cgi?id=232843  .  The read-ahead values
for LV are set to a much lower value than for a md, but can be adjusted
in user-space (my understanding).

Regards,
Eugene Vilensky
evilensky at gmail.com


On Sat, Apr 18, 2009 at 5:25 PM, Sven Eschenberg <sven at whgl.uni-frankfurt.de
> wrote:

> Dear list,
>
> I tried to create a PE+VG+LV ontop of a mdraid. For no obvious reason the
> lvm volume show extremely poor performance - The transferrates are as little
> as 30% of the rates on the md device itself.
> In contrast creating a partition table ontop of the array gives nearly no
> performance impact.
>
> Does anybody have the slightest idea, wht might be going wrong here?
>
> Regards
>
> -Sven
>
> P.S.: I tried aligning the first PE in the VG with the mdraid chunk size,
> no difference whatsoever.
>
> _______________________________________________
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
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