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From: "Miguel Cabeça" <cabeca@ist.utl.pt>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] LVM2 seems to chop performance by 33%
Date: Mon, 14 Jun 2004 12:50:34 +0100	[thread overview]
Message-ID: <40CD910A.9040605@ist.utl.pt> (raw)
In-Reply-To: <40C86F52.4090500@dgreaves.com>

Hi,

> I didn't think lvm2 had such a big performance hit?
>
> 65Mb/s on the raid5 device
> 44Mb/s on the lv
>
Did you try to ajust the read ahead with blockdev on the LV itself?

# blockdev --setra XXXX /dev/sda  (raid5 device, just for comparisson)
# blockdev --setra XXXX /dev/vg/lv (lv)

Try some values for the readahead. On my system I use 2048.

Best regards

Miguel Cabe�a

  parent reply	other threads:[~2004-06-14 11:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-06-10 14:25 [linux-lvm] LVM2 seems to chop performance by 33% David Greaves
2004-06-10 15:05 ` Stuart Harper
2004-06-10 15:31   ` Chris Croswhite
2004-06-10 15:34   ` David Greaves
2004-06-10 16:30     ` Clint Byrum
2004-06-20 18:17       ` David Greaves
2004-06-20 19:53         ` Alasdair G Kergon
2004-06-21  9:55           ` David Greaves
2004-06-14 11:50 ` Miguel Cabeça [this message]
2004-06-14 13:24   ` David Greaves

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