Re: Using Btrfs on single drives

[Duncan <1i5t5.duncan@cox.net>]

Russell Coker posted on Wed, 25 Nov 2015 18:20:25 +1100 as excerpted:

> On Sun, 15 Nov 2015 03:01:57 PM Duncan wrote:
>> That looks to me like native drive limitations.
>> 
>> Due to the fact that a modern hard drive spins at the same speed no
>> matter where the read/write head is located, when it's reading/writing
>> to the first part of the drive -- the outside -- much more linear drive
>> distance will pass under the read/write heads in say a tenth of a
>> second than will be the case as the last part of the drive is filled --
>> the inside -- and throughput will be much higher at the first of the
>> drive.
> 
> http://www.coker.com.au/bonnie++/zcav/results.html
> 
> The above page has the results of my ZCAV benchmark (part of the
> Bonnie++ suite) which shows this.  You can safely tun ZCAV in read mode
> on a device that's got a filesystem on it so it's not too late to test
> these things.

Thanks.  Those graphs are pretty clear.

As you, I'd have thought there'd be far fewer zones (3-4) than it turns 
out there are (8ish).

-- 
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"Every nonfree program has a lord, a master --
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