multi array on single set of disks on AMD raid

[xenn]

I have an ASUS M5A78L-M/USB3 760G / SB710 motherboard with AMD raid.

This motherboard's RAID configuration ROM / BIOS only allows up to two arrays to be configured on a single set of disks; e.g.

If I configure one RAID 10 array on a set of 4 disks with a less-than-full capacity, which I am allowed to do, then the next array I define on this set will NOT give me the same option; I will not be allowed to set a capacity and it will just use and consume the remaining capacity on the disks.

In short, there is a maximum of 2 arrays I can define in RAID 10 on this set of disks.

I am wondering if this is a limitation of the controller or just the configuration screen.

And if it is just the configuration screen, is it easy to mod this? or has it already been done?

That is my question for today.

[xenn]

Please, I would like to bump this.

I have never modded BIOS before and I am also not really in the position to do so today.

Hardware RAID cards like those of Adaptec support creating more than one array on the same set of disks by specifying a capacity that is not full capacity for the disks. That is, they are capable of creating "slices" where each slice is represented to the OS as a unique, individual array (or disk). AMD motherboards to my knowledge (and experience on this board here) do not support creating more than TWO slices. The first array you create you will be able to specify a size. (Capacity). The second one automatically gets max size (remaining capacity) and no option is there for editing the thing.

I assume that the controller (chipset) itself will have no difficulty operating on more than 2 arrays at the same time for the same disks, but I can't be sure. I assume the limitation only exists in firmware and possible even only in the configuration part; but that can't be taken for granted.

There are really two possibilities:

• The firmware is written in some mediocre way to not support expanding the "number" of arrays per diskset to more than 2
  
• The configuration firmware including RaidXpert (the software under Windows) is written in such a way as to not allow the creation of more than 1 size-specified array (capacity-specified) and as a consequence will not allow you creating more than 2 arrays, when in fact it would be possible given minor changes.
  

My hope had been for this thing to fall into category number two: once the required firmware parameters are set; it will have no difficulty whatsoever doing the thing itself. But perhaps there are many places where changes need to happen. One can imagine the structure of the on-disk format to be the first place to look. Then, it must be known whether or not there is any "firmware" based configuration being kept. If the configuration is actually loaded from disk and nothing other than that, it would be easy. Otherwise you/we must check whether the "firmware structures" (persistent memory) are in some way hard-limited to only allow for two arrays (slices) per disk group but this would be weird.

Then, you must check, if the on-disk structures are not limited, and neither is any persistent BIOS memory, whether or not it would be easy to circumvent the limitation in the configuration softwares. This gives two choices: BIOS firmware and RaidXpert. If RaidXpert only has an inhibition in CREATING the slices but not in DISPLAYING them or operating on them, then again stuff would be very easy to patch. In fact, you might consider that only a BIOS mod would be necessary, but I can't be sure about this.

That is really the story today.

However I am very ill equipped to do this myself as of this day of writing. I am just inquiring into information or thoughts, and of course if anyone would be willing to do it, that would be fine too. But any information would be golden here.

Regards, Xen.