Re: LVM

[William Stearns <wstearns@pobox.com>]

Good morning, all,

On Thu, 16 Oct 2008, Steve Hillman wrote:

> ----- "John Fulton" <fultonj@lafayette.edu> wrote:
>
> > Has anyone expanded a Zimbra volume with LVM or does anyone have
> > multiple primary and secondary mail stores on the same server?
>
> take out our redologs. My only real concern about this is how much (if 
> any) overhead LVM adds -- the responsiveness of the redolog volume seems 
> to be the most critical in terms of affecting the user experience (makes 
> sense when you consider that Zimbra does the Right Thing and fsync's all 
> transactions to the redolog before returning an "ok" to the user.)

	My best understanding is that LVM contributes essentially no 
overhead at all.  Converting a logical block to a physical block is a 
lookup in memory that's completely dwarfed by reading from, writing to, 
and/or seeking to the actual sector.
	Cheers,
	- Bill

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William Stearns (wstearns@pobox.com, tools and papers: www.stearns.org)
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