At Thu, 19 Aug 2010 09:54:32 -0500 CentOS mailing list <centos@xxxxxxxxxx> wrote: > > > With the default settings in my Supermicro motherboard CentOS calls my > > SATA drive /dev/hda. Â If in bios setup I change 'Native Mode > > Operation' from auto to 'Serial ATA' it boots up calling the drive > > /dev/sda. Â I keep thinking its likely better under /dev/sda not? Â Any > > problem switching it to that after install? > > So I guess another question here. Is it better to my SATA interface > in Serial ATA mode or AUTO in BIOS? The motherboard calls it sda when > in serial ata mode but hda when in auto mode. Will there be a > performance difference? Yes. SATA is going to be faster. Note: your 'motherboard' is not calling it sda or hda. What your motherboard is doing is either *native* Serial ATA mode or *emulated* Parallel ATA (aka IDE) mode (also known as 'legacy' mode). The linux *kernel* then either sees IDE disk(s) (*emulated* Parallel ATA mode) or native Serial ATA disks, and loads a Serial ATA driver, which uses the SCSI disk abstraction layer (sd). The *native* Serial ATA mode is faster and more feature-rich, such as including things like hot-swapping, should you install a SATA hot-swap bay. This is not possible with IDE disks and the IDE disk driver does not really support it. Also, motherboards with more than 4 SATA ports will only make 4 available when in 'IDE' mode. If there are more than 4 SATA ports on your motherboard, you need to be in native SATA mode to use all of them. This includes any E-SATA ports as well. The only problems with switching after install is: 1) you need to be sure the initrd has the (proper) SATA kernel module(s) in it. If necessary, you'll have to use mkinitrd to re-create the initrd file to include the proper driver modules. 2) /etc/fstab needs to be fixed, either to use LABEL= (rather than /dev/hdaN) and your file systems (including swap) need to have file sytem labels. (LVM volumes won't be a problem.) > > Matt > _______________________________________________ > CentOS mailing list > CentOS@xxxxxxxxxx > http://lists.centos.org/mailman/listinfo/centos > > -- Robert Heller -- 978-544-6933 Deepwoods Software -- Download the Model Railroad System http://www.deepsoft.com/ -- Binaries for Linux and MS-Windows heller@xxxxxxxxxxxx -- http://www.deepsoft.com/ModelRailroadSystem/
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