From: John McMonagle <johnm@advocap.org>
To: linux-raid@vger.kernel.org
Subject: optimum blockdev --setra settings
Date: Mon, 18 Apr 2005 20:55:05 -0500 [thread overview]
Message-ID: <426464F9.5040301@advocap.org> (raw)
Anyone establish optimum blockdev --setra settings for raid on a 2.6 kernel?
There has been some discussions on the lvm mailing list.
In the case of lvm on raid sounds like it's best to use 0 on the md and
disk devices and something around 1024 and 4096 on the lvm devices.
It seems make some sense that it can cause a lot of unneeded reads
particularly if you have a lot of layers and/or a lot of raid5 drives.
My experiments have been inconclusive. At least it seems that setting
read ahead to 0 on the low level devices has no penalty.
John
next reply other threads:[~2005-04-19 1:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-19 1:55 John McMonagle [this message]
2005-04-19 8:17 ` [linux-lvm] Re: optimum blockdev --setra settings David Greaves
2005-04-19 8:17 ` David Greaves
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