xRAID disks....

[Manolis Kiagias]

Wojciech Puchar wrote:
>>
>> I recently removed one pair of disks from a windows "hardware :)" 
>> RAID controller, and upon inserting it into a newly built FreeBSD 
>> system, it was immediately detected by the ar driver, and messages 
>> started coming in, like
>
> is there actually any difference in ar and gmirror/gstripe except that 
> ar is simpler, takes only whole drives and use "hardware RAID ;)" 
> compatible headers ?
>
>> make the disks forget about their previous RAID-life:
>>
>> atacontrol delete ar0
>>
>> Have a look at man atacontrol. I have not tried it, but it is 
>> probably worth a try.
>
>

I've used gmirror on several occasions, and it works well for me. I have 
never used ar, but as I understand this is limited to ata disks (hence 
ar=atapi raid). The geom framework probably provides a lot more features 
and is not limited the way ar is. I would not mind using ar in this 
particular system, but I moved disks one by one, erasing the first one 
(ar was still complaining about the other one missing after I erased it) 
and when I later added the second one, I got a kernel panic. Mind you, 
the ar "signature" or whatever was written in a windows system and may 
not have been exactly compatible. I removed ar from the kernel and 
continued with my usual gmirror stuff (which works flawlessly)