Max Number of Drives Supported by Motherboard BIOS

[James987654321]

Recently, I was puzzled when the BIOS on my expensive Asus motherboard report only 20 drives when there were 24 plugged into multiple SATA controllers. No only are 4 drives not listed in the BIOS, but they are not reported to Linux and the OS sees only 20 drives. Furthermore, it seems fairly random which subset of the 24 are seen upon booting. After contacting Asus tech support, they confirmed that the BIOS only supports 20 SATA devices.

Nowhere on any motherboard manufacturer's website do I see listed the maximum number of drives supported by the BIOS. How can this number be determined other than by trial and error or by writing to each of the manufacturers about each feasible motherboard?

Or do you have recommendations for motherboards that will support larger numbers of drives?

Thanks!

 

[VirtualLarry]

That's pretty brain-dead, if the board cannot recognize drives in all of the mobo's onboard ports. Are you using add-in cards, too, or just the onboard?

And if they aren't seen in Linux, either, then that sounds more like a controller / add-on card mobo resource error (memory windows, etc.) than the BIOS itself. Though, it could be a BIOS bug.

Any change, you could talk them into spinning up a BIOS build for you special, that would allow 24 drives to be seen?

 

[UsandThem]

I wasn't aware of any mainstream Asus boards that supported that many SATA drives (granted I don't run anywhere near that many drives, so it's not something I actively keep track of). You didn't state the model you have, just that it is an "expensive Asus". But with such unique needs, that's probably something to verify before buying a high-end board.

I know from reviews that ASRock had a couple of boards that supported 22 and 18 SATA drives respectively:

http://www.anandtech.com/show/9060/the-asrock-x99-extreme11-review-eighteen-sata-ports-with-haswelle

Maybe it's time to consolidate some of those drives, or move into the server class lineup. 24 SATA drive support on a consumer board is probably not a very high priority for most motherboard manufacturers.

 

[James987654321]

It just never occurred to me that a motherboard BIOS would impose a limit. I am using a workstation motherboard in a server chassis that has 24 hot-plug SATA slots. Add to that two SSDs inside, and it is a total of 26 drives that I would like to have. Unfortunately, the MB supports only 20. I first tried a variety of different SATA controllers, switching drives around, and I was worried about the hot plug back-plane. However, I found that all of the drive slots work fine. Switching SATA controllers made no difference. Switch brives from one controller to another, or between the motherboard SATA ports and PCIe SATA controller ports made not difference. Just if I tried to put in more than 18 hot-plug drives plus the 2 SSDs then (apparently randomly) some of the drives will not work.

What is equally annoying is that this is not one of the specs listed on any of the MB spec sheets, nor do MD reviewers ever mention this issue.

 

[Lorne]

Some motherboards have settings, It might be worth a try to set the drives not to mount in BIOS but let the OS mount them after boot.
Just keep your boot drive in BIOS.

 

[VirtualLarry]

https://support.microsoft.com/en-us/kb/942959

 

[vailr]

I imagine that it's really a specific (Intel?) chipset limit, as to the maximum number of active SATA drives.
In most situations like that, the better methodology would be to instead: set up multiple virtual drives.
Keeping the number of physical SATA drives down to maybe 10 or 12. Or something like that.

 

[Lorne]

Any more out to this?