Server 2012 and 2012 R2 do not allow access to all 7 optical SAS drives?

Question

The following problem occurs with Windows Server 2008 R2, 2012 and 2012 R2, Datacenter or Standard. 
I have an external SAS enclosure with seven optical drives and one hot-swap SAS/SATA bay that connects using two SFF-8088 connectors (no internal SAS expander, etc.).  The purpose is to use the seven bluray writers to write multiple copies of a large
database simultaneously.  The optical drives are also occasionally used to read datasets that come on multiple discs (usually 8-12 per dataset and up to 15 datasets at a time).  Because of the volume, more optical drives are definitely better. 
Regardless of the type of SAS controller used to connect this enclosure, some significant functionality is always missing.
For writing, it is best to connect directly to the optical drives (which do their own buffering) so a HBA would seem better than a hardware RAID controller.  I have tried several HBAs, including LSI-9211, LSI-9240-IT, Dell H310-IT.  In all cases,
Windows only sees four DVD drives and the hot-swap bay.  The drives Windows sees work perfectly for reading and writing.  MegaRAID Storage Manager (LSI controller software) sees all seven optical drives and the hot-swap bay.  LSI says this
must be a Windows problem.  Strangely, if I remove (any) three optical drives and replace them with hot-swap bays, all eight devices are recognized by Windows.
If I use a true RAID controller (tried LSI-9260, Dell H800, Dell H810, HP 812P, IBM 5015), windows and MSM see all seven drives and the hot-swap bay, reads from the optical drives are fine, but writing large discs times out (presumably because of buffering
by the RAID card) so I can't write DVDs.
Is there a way to get Server to recognize all seven optical drives on an HBA?  Ideally, I'd like to add several of these enclosures but I can't even get one working properly!
The system is a Tyan (Dell) MB with dual Xeon E5-2620s and 64Gb RDIMM.  Currently includes LSI-9260 (2Tb SAS 10k in RAID 0), Dell H810 (32Tb SAS in RAID 6), and LSI-9211 (optical enclosure + 3Tb hot-swap).  Just installed Server 2012 R2 Datacenter
for testing.
Any help would be greatly appreciated.

Answer 1

I've had the experience of working as a validation engineer for Intel, who at the time was developing a SAS/SATA storage controller chipset for thier new xeon processors. The chipset was included in their motherboard offerings. I validated the linux driver,
which is now included in the linux kernel as of the 3.x series kernel.
My first question is, what type of SAS enclosure are you using for your optical drives/hot swap bay? You will be surprised at how many enclosures don't actually provide a 100% direct-attached storage configuration, and instead opt to work as a mini expander
instead. In our validation, we tested several SAS enclosures, and we found several that even though they were advertised as direct-attached enclosures, by inspecting the data transmission with a SAS protocol analyzer we found communication over SMP (Serial
Management Protocol).
To ensure it is NOT the enclosure causing the anomaly, i'd connect the 7 optical drives directly to each storage controller unit (or sff-8087). These cards can support around 256 devices via expander attached configuration, as that is how many sas addresses
the scu's can support. Either way, they can only support a maximum of 8 devices direct-attached (4 per SCU). I would use a multi-line SFF-8087 SATA breakout cable to directly connect your optical drives to the HBA, 4 on SCU0 and the other 3 on SCU1.
I find it strange that LSI's storage manager can see all of the drives, but windows cannot. Since the SAS protocol allows for the ATAPI cmd set to be sent via scsi commands, the only thing I can think of is if windows can only recognize a certain amount
of SAS-addresses utilizing the ATAPI cmd set. Technically, it should only be limited by the number of devices the hba can support, and in either LSI thats 256. Otherwise the enclosure may be doing something funny with the initiator (SCU), where one initiator
may take precedence over the other. Again, testing a direct connection with a SFF-8087 SATA breakout cable will eliminate the enclosure as a factor.
I can understand from a developer perspective for the desire to have windows recognize the devices instead of relying on the lsi storage app. Firstly, that app is monstrous and unwieldy. Secondly, it does not allow for customized solutions/scripting to fully
access the optical devices, since you have to interact w/ lsi's storage mgr. 3rd, this should simply work if MS is fully compliant with the SAS protocol.
Finally, I want to make sure everyone is aware that a fully compliant 6G SAS compliant device will support SSP (Serial SCSI protocol), SMP (Serial Management Protocol), and STP (Sata Tunneling Protocol). STP basically defines how SATA devices can inter-operate
within the sas fabric by tunneling ATA commands via the SCSI cmd set. This is a basic functionality guaranteed within the overall SAS protocol; if your HBA supports SAS & SATA, it will support SSP, SMP, and STP frames (this is usually always listed on
the HBA), and therefore it will fully support SATA devices. A SAS device will support SSP & SMP. A SATA-only HBA will support the ATA cmd set only (and thus, cannot inter-operate within a SAS fabric).
Please note that at the very least, a direct-attached configuration should provide the number of Storage Controller Units x 4 fully working SATA devices (generally each internal SFF-8087 is a scu, most HBA's have a min of 2 SCU's, and 4 directly addressable
devices per SCU (8 direct attached devices total). Generally, any issues that will arise from SATA devices will be the result of expander-attached configurations. There are many points a SATA device can experience errors in a expander-attached configuration,
from the routing mechanism being utilized (table vs subtractive), to the type of expander being used (fan-out vs edge expander). Expanders will generally at least support 1 method of routing, if not both, and may or may not support multi-level configurations
(this is specifically dependent on the hba). It was not uncommon in our testing to come across expanders that would work great w/ SAS & SATA w/ 1 level expander, but fail to communicate with SATA devices past 2 or more levels. This falls on the responsibility
of the HBA, specifically the driver for the OS.
More Info on SATA Tunneling Protocol (STP): 
http://www.serialstoragewire.net/Articles/2004_0225/developer_article_2_feb.html