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From: Krzysztof Halasa <khc@pm.waw.pl>
To: Mark Knecht <markknecht@gmail.com>
Cc: "Jeff Moyer" <jmoyer@redhat.com>,
	"Rogier Wolff" <R.E.Wolff@bitwizard.nl>,
	"Greg Freemyer" <greg.freemyer@gmail.com>,
	"Bruno Prémont" <bonbons@linux-vserver.org>,
	linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org
Subject: Re: Slow disks.
Date: Mon, 27 Dec 2010 19:20:24 +0100	[thread overview]
Message-ID: <m3pqsnnklz.fsf@intrepid.localdomain> (raw)
In-Reply-To: <AANLkTi=qAGCFU0u8joKVR4o4QQaRZt1XWfOPSt8eiD3r@mail.gmail.com> (Mark Knecht's message of "Sun, 26 Dec 2010 15:38:51 -0800")

Mark Knecht <markknecht@gmail.com> writes:

> Even when I got that part worked out I found that the drives just
> didn't work well in a RAID. The mdadm list led me to believe that the
> root cause was the lack of TLER in the firmware. I don't know how to
> show that's true or not...

But TLER only matters when the drive can't read a sector. For a normal
drive which can easily read all its sectors (at least without retrying
for several seconds) TLER doesn't matter.

Alignment, sure. Personally I'd use whole disks (not partitions) for
RAID-5 and partition the resulting /dev/md* instead, taking into account
even longer "sector" size.

Or better, use RAID-1 (or RAID-10) with 4 KB block fs, partition
/dev/md* with 4 KB alignment, and avoid all these issues. Disks aren't
that expensive now.
-- 
Krzysztof Halasa

  parent reply	other threads:[~2010-12-27 18:20 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20101220141553.GA6088@bitwizard.nl>
2010-12-20 18:06 ` Slow disks Bruno Prémont
2010-12-20 18:32   ` Greg Freemyer
2010-12-22 10:43     ` Rogier Wolff
2010-12-22 15:59       ` Greg Freemyer
2010-12-22 16:27       ` Jeff Moyer
2010-12-22 22:44         ` Rogier Wolff
2010-12-23 14:40           ` Jeff Moyer
2010-12-23 17:01             ` Rogier Wolff
2010-12-23 17:47               ` Jeff Moyer
2010-12-23 18:51                 ` Greg Freemyer
2010-12-23 19:10                   ` Jaap Crezee
2010-12-23 22:09                     ` Greg Freemyer
2010-12-24 11:40                       ` Rogier Wolff
2010-12-26 23:05                         ` Greg Freemyer
2010-12-27  0:27                           ` Rogier Wolff
2010-12-27  7:21                             ` Stan Hoeppner
2010-12-24 10:45                 ` Rogier Wolff
2010-12-26 23:38         ` Mark Knecht
2010-12-27  0:34           ` Rogier Wolff
2010-12-27  3:12             ` Mark Knecht
2010-12-27 18:20           ` Krzysztof Halasa [this message]
2010-12-24 13:01       ` Krzysztof Halasa
2010-12-24 15:24         ` Michael Tokarev
2010-12-24 20:58           ` Krzysztof Halasa
2010-12-25 12:14           ` Rogier Wolff
2010-12-25 12:19             ` Mikael Abrahamsson
2010-12-26 21:40             ` Rogier Wolff
2010-12-26 23:17               ` Greg Freemyer
2010-12-26 23:49                 ` Rogier Wolff

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