I've had a good look round at the howtos and the archives of this list, and I'd like to try and summarise the situation with PDC20276 as I understand it. I am fairly new to RAID, but not Linux.
I just got ataraid working with RH7.3 (plus all updates) and kernel 2.4.20-19.7 (custom, with drivers compiled in)
As I understand it, the hardware controller does no hardware raid. This was a big surprise to me, as I thought it was a RAID controller, but I guess the intention was to always do it in the driver? (even though the PDC bios is happy to tell me it has a raid1 mirrored array)
I have seen a post implying that hardware raid is coming for this controller. Is that correct?
I also saw that the pdc and ataraid drivers crash the system if a disk goes. I know you get what you pay for with OS, but this is a real shame. I need security not performance, and I guess the only use of RAID1 here is that I still get a working disk after the reboot. At least I can autonotify if the system crashes, to find out about the disk ;-) small consolation.
In the light of this, what use is the PDC hardware. Is it not just mainly an IDE controller, or have I missed something.
Is the equivalent of what I have not the same as two ide drives and md software raid? I read that md does not crash the system if it loses a disk. Why would anyone then use ataraid? Is that easier to use with 'raid' controllers.
If I wanted to switch from ataraid to md, is that easy with my PDC20276. Should I keep it in RAID mode (or IDE) Should I just have the kernel see two ide drives, as it currently does, and use md (yes, I won't mix ide and ataraid ;-)
Many thanks for any answers - I'm trying to get my head round all this.