DA Forsyth iwrtech at
Tue Aug 26 08:15:25 UTC 2008

On 26 Aug 2008 , freebsd-questions-request at entreated 
 "freebsd-questions Digest, Vol 230, Issue 4":

> Message: 25
> Date: Mon, 25 Aug 2008 22:29:08 -0600
> Subject: SATA, RAID and AHCI
> Hi,
> This question is about the storage settings for this board (ASUS' name
> for it is "Storage Configuration").  In the CMOS (or whatever it's
> called these days, just out of curiousity, will FreeBSD support things
> like OpenBoot or UEFI on i386, sorry for the digression), I found
> where to turn the "Storage Configuration," as ASUS calls it, from
> "IDE," to "RAID," or "AHCI."  It's currently set to "IDE" because when
> set to RAID the MOBO apparently kept trying to put the SATA DVD drive
> as part of the RAID and when set to AHCI mode the install had hundreds
> of, "can't create symlink, no inodes free," during the copying of the
> files into the newly created file systems. 

strange things.  I have an Intel 965 board which has similar 
settings.  I had no trouble installing 7 Release using the RAID 
setting.  There is a ctrl+F10 or somesuch keypress during boot which 
takes one into the BIOS RAID setup, where you can choose which drives 
go into the RAID, and what form of RAID it is (mine is RAID5 across 
4x400Gb SATA drives).  The machine boots off 2x80G IDE drives in a 
gmirror arrangement.  Strangely, FBSD still recognizes the 4 SATA 
drives as individuals, and then loads the ar driver for the raid 

> Now, I'm a complete neophyte to making these SATA RAID systems. 
> What's the magic to making it work, and how do you keep the DVD drive
> from being part of the RAID?  Also, what should be done for AHCI mode? 
> It looked as though in this mode the drives would perform *much*
> faster. 

RAID mode is what you want to make work.

As to speed.  my home machine runs Fedora Core and under FC5 I could 
not set to anything but 'IDE legacy mode' where it mapped all the 
SATA devices into the IDE space.  This severely affected access 
speed.  Since I use the box for multitrack sound recording, this was 
a big problem.   As soon as I could I upgraded to FC6 which has 
support for native SATA mode and now I get 50MB/s sustained write 
speed.  much happier writing 8 tracks at 48khz (-:

So, I suggest checking the BIOS for setup options that allow you to 
spec the RAID config.

oh, and replace the onboard lan with an Intel card.  they rock

       DA Fo rsyth            Network Supervisor
Principal Technical Officer -- Institute for Water Research

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