[mythtv-users] Anyone using RocketRAID?

[Brian Wood]

On Mar 15, 2008, at 3:25 PM, Boleslaw Ciesielski wrote:

> Brian Wood wrote:
>> As I understand it, and in my experience, a hardware RAID card  
>> shouldn't
>> care about what OS it's running on, or what kernel, or anything else.
>>
>> The card should have its own BIOS, including a built-in program for
>> creating and testing arrays. It should appear to the OS as a single
>> drive, of the type it supports, or possible multiple single drives.
>>
>> So I can't see how it would make any difference what distro or kernel
>> you are running, it should just appear to be a drive or drives.
>
> You still need a kernel driver for the controller. Most (if not all)
> hardware RAID cards require special drivers (just as most SCSI and  
> SATA
> non-raid controllers do). The point that John made was to make sure  
> that
> the drivers are in the stock kernel, not just available for download
> from manufacturers web site.
>
> Actually, a lot of RAID cards do have drivers in the stock kernel but
> there is often a lag until the very latest cards are supported (like
> with anything else).

Good point. Some (if not all) the Adaptec RAID controllers mimic non- 
RAID SCSI controllers that are supported by the kernel, and thus do  
not need a specific driver for the RAID controller.

Then there is the "Zero Channel" RAID that some Intel motherboards  
support, which integrate the on-board (on the mobo that is) SCSI  
controller into the RAID controller, again not needing anything other  
than the basic SCSI controller being supported. This is (was) normally  
found on server class mobos and not consumer desktop units.

But anything new will of course take time to get integrated into the  
kernel, and even longer to become reliable and stable.

Kernel modules supplied by the vendor are limited to specific kernels  
unless the source is supplied, and even then if things like symbols  
change in the kernel they can be rendered useless.

A good example is the nVidia video module(s), which can normally be  
compiled for any kernel even though full source is not provided, but  
can have problems with major kernel upgrades.

And, as was pointed out indirectly, "Linux support" can sometimes be a  
marketing tool and not an accurate description of what a vendor is  
doing. Too often they see it as a one-time coding expense and not a  
continuing commitment.

beww