AHCI/ATA_CAM for dummies?

Vincent Hoffman vince at unsane.co.uk
Sat Dec 12 22:46:04 UTC 2009

Doug Barton wrote:
> I'd like to test the new stuff, but my main concern at this point is
> that I am not 100% sure how to change my fstab, what will happen if I
> need to revert, etc. I'm sure I probably _could_ figure it out, but it
> would save me a lot of time if someone could write down really
> explicit step-by-step instructions ... put this in your kernel config,
> do this to fstab, do this if it blows up, etc.
> Any takers?  :)
> Doug
For me trying ahci was very easy.
boot using the usb image, use the fixit environment.
I  use ufs so I used tunefs to label all my partitions.
tunefs -L ROOTFS /path/to/rootfs
and so on for all my ufs partitions.
and then for swap,
glabel label SWAP /dev/ad1p1    (or your path to swap partition)

next mount the root filesystem and edit the fstab.
mkdir -p /mnt/rootfs
mount /dev/ufs/ROOTFS /mnt/rootfs
vi /mnt/rootfs/etc/fstab

my fstab looks like

/dev/ufs/SSDROOT        /       ufs     rw,noatime      1       1
/dev/ufs/SSDUSR /usr    ufs     rw,noatime      2       2
/dev/ufs/SSDVAR /var    ufs     rw,noatime      2       2
/dev/ufs/TMP   /tmp    ufs     rw,noatime      2       2
/dev/label/SWAP none    swap    sw      0       0
/dev/ufs/SCRATCH        /scratch        ufs     rw,noatime      2       2

but adapt to fit.

I then added
to  /mnt/rootfs/boot/loader.conf
and rebooted.

as yet I havent tried the rest of the ATA_CAM stuff though.

using labels means switching back is easy too (I switched back for a bit
until i found the latest smartmon tools supports the ahci ada devices.)


(obviously now I've sent this I'm bound to have forgotten something but
it really was very simple.)

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