From: Michal Soltys <soltys@ziu.info>
To: Jon Nelson <jnelson@jamponi.net>
Cc: linux-raid@vger.kernel.org
Subject: Re: Linux RAID Partition Offset 63 cylinders / 30% performance hit?
Date: Thu, 20 Dec 2007 14:01:40 +0100 [thread overview]
Message-ID: <476A67B4.3020107@ziu.info> (raw)
In-Reply-To: <cccedfc60712191412j27256304p185d6d06e27d9ebe@mail.gmail.com>
Jon Nelson wrote:
>
> That, for me, is the next question - how can one educate LVM about the
> underlying block device such that logical volumes carved out of that
> space align properly - many of us have experienced 30% (or so)
> performance losses for the convenience of LVM (and mighty convenient
> it is).
>
When you do pvcreate you can specify --metadatasize. It will add padding
just to hit next 64K boundary.
So i.e. if you do
#pvcreate --metadatasize 256K /dev/sda
your metadata will have 320K
but with
#pvcreate --metadatasize 255K /dev/sda
it will have 256K
After that, lvm extents will follow - with the size specified during
vgcreate. Also I tend to use rather large sized extents (512M), as I
don't really need the granularity offered by the default 4M.
next prev parent reply other threads:[~2007-12-20 13:01 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-19 14:50 Linux RAID Partition Offset 63 cylinders / 30% performance hit? Justin Piszcz
2007-12-19 15:01 ` Mattias Wadenstein
2007-12-19 15:04 ` Justin Piszcz
2007-12-19 15:06 ` Jon Nelson
2007-12-19 15:31 ` Justin Piszcz
2007-12-20 10:37 ` Gabor Gombas
2007-12-19 17:40 ` Bill Davidsen
2007-12-19 17:37 ` Jon Nelson
2007-12-19 17:37 ` Jon Nelson
2007-12-19 17:55 ` Justin Piszcz
2007-12-19 19:18 ` Bill Davidsen
2007-12-19 19:44 ` Justin Piszcz
2007-12-19 21:31 ` Justin Piszcz
2007-12-20 15:18 ` Bill Davidsen
2007-12-20 15:00 ` Justin Piszcz
2007-12-20 10:24 ` Gabor Gombas
2007-12-20 10:33 ` Gabor Gombas
2007-12-19 21:44 ` Michal Soltys
2007-12-19 22:12 ` Jon Nelson
2007-12-20 13:01 ` Michal Soltys [this message]
2007-12-19 21:59 ` Robin Hill
2007-12-19 22:03 ` Justin Piszcz
2007-12-25 19:06 ` Bill Davidsen
2007-12-29 17:22 ` dean gaudet
2007-12-29 17:34 ` Justin Piszcz
2007-12-30 1:33 ` Michael Tokarev
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