From mboxrd@z Thu Jan  1 00:00:00 1970
From: Axel Reinhold <axel@freakout.de>
Message-Id: <200401201848.i0KIm9iW017304@bongo.freakout.de>
Subject: Re: [linux-lvm] LVM2 migration on 2.4.24 troubles - prepare for 2.6
In-Reply-To: <20040119171824.S18942@uk.sistina.com> from Alasdair G Kergon at
 "Jan 19, 2004 05:18:24 pm"
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Date: Tue Jan 20 17:06:01 2004
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According to Alasdair G Kergon:
> On Sat, Jan 17, 2004 at 10:06:11PM +0100, Axel Reinhold wrote:
> > Are there incompatibilities regarding snapshots with LVM1/2?
> 
> Yes - snapshots are implemented differently: the on-disk data
> is different.
> 
> Always drop snapshots before switching between LVM1 / LVM2.
> 

Dear Alasdair,

thanks for your answer.  I use snapshots intensively.  I
currently have 6 monthly, 5 weekly and 7 daily snapshots active
with a rotating algorithm.

Does the new implementation copy dirty blocks also in "all"
active snapshots or is it now possible to use the cow-blocks
"cross-snapshot"?  I mean that a new dirty block is only copied
into the oldest snapshot and all the other ones can use that one.
NetApp's Filer does it this way.

Regards
Axel Reinhold

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