Re: Re: LVM on dmraid breakage

Alasdair G Kergon <[email protected]> Tue, 7 Aug 2007 22:50:20 +0100

Newsgroups	gmane.linux.kernel.device-mapper.devel,gmane.linux.ataraid,gmane.linux.lvm.general
Organization	Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE.
Message-ID	<[email protected]>

On Fri, Aug 03, 2007 at 02:10:02PM -0400, Phillip Susi wrote:
> Where does lvm store state 
> information right now?  In conf files in /etc isn't it?  

It uses an untrusted cache in /etc/lvm as hints to speed up its
processing if the hints prove to be still correct.  It can't ever trust
because things can change on the system without lvm2's knowledge.  And
device scanning causes us no end of problems - particularly in a
clustered environment.  The new model should provide us with a
completely-reliable cache.

And why does lvm2 today have to include code to check for partition
tables, md devices, filesystems etc.?

If all these components co-operated through common interfaces there'd be
no need!

Alasdair
-- 
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