Hello mickjohansen,   The T340 supports up to eight hard drives maximum.  Page 13 - [URL]   The Mini-SAS would be used if you are using the S140 software controller connected to the backplane. You currently have the H330 connected to the backplane.  You cannot use both.   Please let me know if this helps.  
Hi, Just received my T340 and it looks like great value for the money. As this will mainly be a storage server, I will fill in the 8 bays connected to the PERC 330 with 10-16TB spindles (not sure which size yet) in a RAID6. Pure storage. Looking to maximize the storage capacity in the server, I can see the onboard mini-SAS allows for 4 more SATA drives controlled by the PERC S140. The available 3x5.25" should be able to hold a 4x3.5" SATA rack, which should fit perfectly with those. And then there are two SATA onboard as well. What I cannot find out, however, if these overlap with the drives available via the mini-SAS and which cable I should buy to utilize this? If both are supported, I would like to end up with 8+4 storage drives (RAID6+RAID1) and 2 boot drives (RAID 1). Please advice, what is the max amount of drives the server can handle internally and which cable should I buy to utilize the mini-SAS? Kind regards, Mick Johansen,     
How to utilize the onboard mini-sas on T340