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From: Volker Armin Hemmann <volkerarmin@googlemail.com>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] 1-Terabyte drives - 4K sector sizes? -> bar performance so far
Date: Wed, 10 Feb 2010 09:43:04 +0100
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On Mittwoch 10 Februar 2010, Iain Buchanan wrote:
> On Wed, 2010-02-10 at 07:31 +0100, Volker Armin Hemmann wrote:
> > On Mittwoch 10 Februar 2010, Iain Buchanan wrote:
> > > so long as you didn't have any non-detectable disk errors before
> > > removing the disk, or any drive failure while one of the drives were
> > > removed.  And the deterioration in performance while each disk was
> > > removed in turn might take more time than its worth.  Of course RAID 1
> > > wouldn't suffer from this (with >2 disks)...
> > 
> > Raid 6. Two disks can go down.
> 
> not that I know enough about RAID to comment on this page, but you might
> find it interesting:
> http://www.baarf.com/
> specifically:
> http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt

to give you an example, why raid 1 is not a good choice (and raid 10 too).

You have two disks configured as mirror. They report different blocks. Which one 
is the correct one?

And suddenly your system has to guess and you are very out of luck.

Another reason, the author of that text stresses that you have to do more 
writes. Newsflash: with Raid1 every single block has to be written twice. So if 
you use additional writes against Raid5, Raid1 is instantly disqualified.


You shouldn't listen to people with an agenda.

This is almost as bad as the site that claimed that SATA is much worse than 
PATA in every single aspect ...