[CentOS] Very slow disk performance on CentOS 4.5
Ross S. W. Walker
rwalker at medallion.com
Fri Aug 31 17:43:47 UTC 2007
From: centos-bounces at centos.org
[mailto:centos-bounces at centos.org] On Behalf Of Bart Schaefer
>
> On 8/31/07, Alfred von Campe <alfred at von-campe.com> wrote:
> > The are all SATA drives (2 HDDs and 2 optical drives). But because
> > there are two controllers, one of the HDDs shows up as /dev/hda and
> > the other as /dev/sda.
>
> If it's showing up as /dev/hda, it's probably being accessed in legacy
> IDE compatibility mode or some such thing. Check your BIOS.
>
> (With CentOS 3, any time I upgrade the kernel, I have to switch my
> SATA drives into legacy mode before lilo will write the boot sector
> properly, and then switch them back again when rebooting.)
Yes, I was going to say this too, make sure the SATA settings in the
BIOS are all set to SATA operation and not "legacy", then you should
see /dev/sda and /dev/sdb and all DMA, IO size, NCQ and multiple sector
settings will be properly negotiated at start-up.
To set these via hdarpm:
hdparm -c 1 /dev/hda (for 32-bit)
hdparm -d 1 /dev/hda (for DMA)
hdparm -m 16 /dev/hda (multiple sector IO = 16 sectors)
These can be combined to: hdparm -c 1 -d 1 -m 16 /dev/hda
-Ross
______________________________________________________________________
This e-mail, and any attachments thereto, is intended only for use by
the addressee(s) named herein and may contain legally privileged
and/or confidential information. If you are not the intended recipient
of this e-mail, you are hereby notified that any dissemination,
distribution or copying of this e-mail, and any attachments thereto,
is strictly prohibited. If you have received this e-mail in error,
please immediately notify the sender and permanently delete the
original and any copy or printout thereof.
More information about the CentOS
mailing list