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Date: Mon, 25 Nov 2013 18:43:26 -0700 (MST)
From: Warren Block <wblock@wonkity.com>
To: Eric Browning <ericbrowning@skaggscatholiccenter.org>
Subject: Re: Performance difference between UFS and ZFS with NFS
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On Mon, 25 Nov 2013, Eric Browning wrote:

> I've tried to 4K align these SSDs with gnop but they are currently ashift
> 9.

Those are two different things.  Alignment is controlled by partition 
starting block and size.  Both should be integer multiples of 4K.

Using gnop to force ashift=12 just makes sure ZFS is using 4K blocks, it 
does not force alignment.