Opinions on Adaptec SATA HostRAID?

[Chris Snook]

Steve Snyder wrote:
> On Wednesday 19 March 2008 2:53:53 pm Chris Snook wrote:
>> Steve Snyder wrote:
>>> I'm thinking of using the embedded Adaptec SATA HostRAID
>>> functionality on my Supermicro X7DWA-N motherboard.
>>>
>>> Does anyone have any experience using Adaptec's HostRAID with Fedora
>>> 7/8/9?  Any success or horror stories to relate?
>>>
>>> Any information would be appreciated.
>> HostRAID is just software RAID implemented in a device driver.  It was
>> originally intended for use with operating systems that lack a generic
>> software RAID implementation.  Since Linux has a robust and
>> well-optimized generic software RAID implementation (two of them,
>> actually), it's rather silly to use HostRAID under Linux.
> 
> Thanks for the info, Chris.
> 
> I'm a total RAID newbie and thought that the HostRAID BIOS support and 
> Linux device driver worked together, rather than being redundant.

That's not entirely false.  Recent device mapper will attempt to detect a 
HostRAID configuration and emulate it with dm-raid, but this isn't foolproof, 
and offers no benefit over simply configuring dm-raid directly.  If you want to 
use mdadm for software RAID, you should definitely disable HostRAID entirely, as 
it will only cause problems.

Before you ask, I have no recommendations regarding dm-raid vs. mdadm.  Both 
generally work fine.  dm-raid is newer and shinier, while mdadm is more 
established and better documented.

-- Chris