Date: Wed, 23 Jan 2013 21:53:27 +0000 From: Chris Rees <utisoft@gmail.com> To: Michel Talon <talon@lpthe.jussieu.fr> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Mark Felder <feld@feld.me> Subject: Re: ZFS regimen: scrub, scrub, scrub and scrub again. Message-ID: <CADLo83_qpgz1W=qbQoaYKQgGgsoeLEx1hdgZKZ9xiFQyiR7AOQ@mail.gmail.com> In-Reply-To: <101D6382-BF57-43EB-A5FA-A63D4062F5FD@lpthe.jussieu.fr> References: <101D6382-BF57-43EB-A5FA-A63D4062F5FD@lpthe.jussieu.fr>
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On 23 Jan 2013 21:45, "Michel Talon" <talon@lpthe.jussieu.fr> wrote: > > On Wed, 23 Jan 2013 14:26:43 -0600, Chris Rees <utisoft@gmail.com> wrote: > > > > > So we have to take your word for it? > > Provide a link if you're going to make assertions, or they're no more > > than > > your own opinion. > > I've heard this same thing -- every vdev == 1 drive in performance. I've > never seen any proof/papers on it though. > > > first google answer from request "raids performance" > https://blogs.oracle.com/roch/entry/when_to_and_not_to > > Effectively, as a first approximation, an N-disk RAID-Z group will > behave as a single device in terms of delivered random input > IOPS. Thus a 10-disk group of devices each capable of 200-IOPS, will > globally act as a 200-IOPS capable RAID-Z group. This is the price to > pay to achieve proper data protection without the 2X block overhead > associated with mirroring. Thanks for the link, but I could have done that; I am attempting to explain to Wojciech that his habit of making bold assertions and arrogantly refusing to back them up makes for frustrating reading. Chris
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