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Date: Mon, 16 Jan 2012 12:05:53 +0000
Message-ID: <CAFHbX1LH1CW4a1XMkMpdDttbTSTnhDL65VW=UzyC6qFjKGnS2Q@mail.gmail.com>
From: Tom Evans <tevans.uk@googlemail.com>
To: Dieter BSD <dieterbsd@engineer.com>
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Cc: freebsd-performance@freebsd.org
Subject: Re: cmp(1) has a bottleneck, but where?
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On Sun, Jan 15, 2012 at 11:32 PM, Dieter BSD <dieterbsd@engineer.com> wrote:
> I recently read somewhere that zfs needs 5 GB memory for each 1 TB of disk.
> People that run zfs obviously don't care about using lots of memory.

You read incorrectly. To run zfs with dedup needs ~ 5GB of RAM per TB,
but this depends upon file size.

However, the majority of ZFS users do not use dedup. My pool is 18 TB
with 8 GB of RAM, of which ZFS can only access 4 GB.

Cheers

Tom