Date: Thu, 07 Jun 2007 05:48:39 +0200 From: Fluffles <etc@fluffles.net> To: matthew@digitalstratum.com Cc: Lukas Razik <lukas@razik.de>, freebsd-hardware@freebsd.org Subject: Re: Promise TX2300 array not detected. Message-ID: <46678017.6080602@fluffles.net> In-Reply-To: <46674449.6090109@digitalstratum.com> References: <4662E72B.70003@digitalstratum.com> <4662F5BF.4090709@razik.de> <4663496A.40202@digitalstratum.com> <466718DC.2030600@razik.de> <46674449.6090109@digitalstratum.com>
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Matthew Hagerty wrote: > Hey Lukas, > > Thanks for the response! Wow, that seems like a messy procedure, but > I'll go see if I can get things working. I only have three questions > at this point: > > 1. What is atacontrol doing that lets FreeBSD see the array? > 2. After using atacontrol, is this now a software or hardware array? > 3. Is there anyone I can send my card to who can fix FreeBSD? If i understand correctly, you're using firmware RAID, also called fake RAID. It's called Fake RAID because the controller itself does not handle the "RAID thing" but rather leaves it to drivers (software) to implementent the RAID0/RAID1 handling, just like software RAID would. In Windows, you get this working by using drivers, whereas for Linux and BSD often no drivers are provided. Instead, FreeBSD is able to read the so called "meta information" stored on the drives to read "oh hey this disk is said to be part of a RAID0 array, and this is disk0 of in total 2 disks with x KB stripesize". And later it finds the other disk part of the array, it can then use it's own RAID0 or RAID1 implementation and create software RAID on it, just like a Windows driver would do it. You see, even firmware/fake RAID is still software RAID; its all implemented in the drivers. The only difference to true software RAID is that it adds bootstrap support whereas one cannot boot from a software RAID0 array. So to answer your first two questions: 1) atacontrol is used to create a RAID0 array using manual parameters, while normally these parameters would be read from the on-disk metadata (in the drive's last sector) 2) it is and always has been a software array, also in windows. only if the host OS cannot see the physical disks behind the controller you're talking about hardware RAID. Those controllers usually cost over 200 dollar; they are the real thing. So to be quite blunt.. your hardware controller gives you software RAID, not hardware RAID. Hope this gives some background. Good luck, - Veronica
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