From: Linda Walsh <lkml@tlinx.org>
To: dE <de.techno@gmail.com>
Cc: util-linux@vger.kernel.org
Subject: Re: fdisk and 2048 sectors obsession.
Date: Tue, 28 Oct 2014 10:11:34 -0700 [thread overview]
Message-ID: <544FCE46.2090709@tlinx.org> (raw)
In-Reply-To: <544FA923.5080205@gmail.com>
dE wrote:
> 2048 is Windows behavior ported to utils-linux. It's pointless.
Not if you move to any sort of RAID and want efficiency. Then 64k or 256k
alignment is minimal. If you start at 1M, then layering other things on
top, -- like default lvm blocks of 4M will still line up at 1M. Then
when you
layer RAID aware software like xfs on top of those, it can know how to do
allocations and layout to allow optimal I/O on most RAID sizes.
Anyone who uses RAID5 or RAID6 based underlying HW will appreciate
file systems with full alignment to the underlying device stripes. Partial
writes on those types of RAID's (or derivatives) requiring a complete
read-modify-write cycle the size of the data stripe, so any underlying
disk misalignment will really cause performance pain...
But having all the disks start at 1M, you can usually move complete
disk images around on devices and not get hurt by alignment
issues.
next prev parent reply other threads:[~2014-10-28 17:29 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-27 18:43 fdisk and 2048 sectors obsession dE
2014-10-27 19:07 ` Felix Miata
2014-10-28 3:24 ` dE
2014-10-28 3:55 ` Felix Miata
2014-10-28 4:30 ` dE
2014-10-28 5:53 ` Felix Miata
2014-10-28 7:32 ` Karel Zak
2014-10-28 7:49 ` Felix Miata
2014-10-28 8:48 ` Martin Steigerwald
2014-10-28 8:47 ` Martin Steigerwald
[not found] ` <544F3B20.7090109@gmail.com>
2014-10-28 14:33 ` dE
2014-10-28 17:11 ` Linda Walsh [this message]
2014-10-29 14:28 ` Dale R. Worley
2014-10-28 7:53 ` Karel Zak
2014-10-28 12:38 ` Martin K. Petersen
2014-10-28 14:53 ` dE
2014-10-28 15:35 ` Theodore Ts'o
2014-10-29 16:40 ` dE
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