From owner-freebsd-current@FreeBSD.ORG  Mon Dec 19 23:01:16 2011
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To: Alexander Best <arundel@freebsd.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Mon, 19 Dec 2011 22:56:33 GMT."
	<20111219225633.GA77147@freebsd.org>
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Date: Mon, 19 Dec 2011 23:01:15 +0000
Message-ID: <78665.1324335675@critter.freebsd.dk>
Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org
Subject: Re: can a wrong alignment cause a decrease in a hdd's life
	expectancy?
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In message <20111219225633.GA77147@freebsd.org>, Alexander Best writes:

>no problem. so will the improper alignment also not cause a life expectancy
>shortage in case of a hdd (non-flash-based)?

Well, theoretically you will have more track-to-track seeks, as some
blocks will span cylinders, but I doubt that will have measurable
impact on lifetime, compared with the gains you could harvest if you
spin it down for even just 1 hour a day...

Read-Only/Read-Write makes no difference that I know of for hard-disks.

>and one other question: the hdd also supports usb 3. will the improper
>alignment have any effect (speed wise) when connected via usb 3, or is even
>usb 3 too slow to notice the performance drop due to the improper alignment?

Again: I doubt it will be measurable.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.