Stuck on mountroot command line after connecting Dell MD1200 SAS Powervault to Dell R510 by external HBA flashed to IT mode

[_Perkinje_]

Setup:

• Dell R510
  • 2x Intel Xeon X5660 2.8GHz 6 core processors
  • 128GB (8 x 16GB) PC3-10600R DDR3
  • 2 Enterprise 3TB SAS drives and 6 WD HGST 10TB SAS, Boot device is one of the 3TB drives (yes, I know not great but will convert to sata-dom soon) connected through Dell H200 w/ LSI 9210-8i P20 IT mode
  • Intel E1G44HTBLK 4 port 1GB NIC
  • LSI 9200-8e external SAS HBA P20 IT mode
• MD1200 Powervault, connected through two mini-SAS cables (SFF-8088)
  • 8 Enterprise 3TB SAS drives

I'm running TrueNAS 12 on a Dell 510 server and I tried to expand my storage with a MD1200 Powervault connected to the 510 with two mini-SAS cables. The 510 boots fine by itself. If I attach the MD1200 it stops on the mountroot cli. I get errors saying "Root mount waiting for: CAM usbus2" and "Mounting from zfs:boot-pool/ROOT/12.0-U3 failed with error 2". If I remove the MD1200, boots fine. Typing "?" lists out all the drives in the 510 and 1200. I'm not sure how to tell which is my boot drive. Searching the forums I've found others with a similar issue but they're mainly trying to boot from a usb or have a failed boot drive to get this error. I can get it to boot with "zfs:boot-pool/ROOT/default" but I then have no ip address listed to connect to the gui.

Any help with this would be great. I'm very much a NOOB with TrueNAS, so be gentle.

 

[_Perkinje_]

I figured it out. I wasn't aware the MD1200 were hot-pluggable. Booted TrueNAS and then turned on the SAS enclosure. Now all drives show up.