I got a Supermicro storage server some years ago - a SuperStorage 6047R-E1R36N to be specific. It came originally equipped with an LSI/Broadcom 2108 SAS2 RAID AOC HBA which was connected to a front backplane (Supermicro BPN-SAS2-846EL1) supporting 24 drives and a rear backplane (Supermicro BPN-SAS2-826EL1).
Because I wanted to use software RAID rather than hardware raid, I swapped out the 2108 with an LSI 9207-8i and connected it to the front and rear backplanes in the same way as the 2108 it was replacing. Firmware is 20.00.07.00-IT.
Drives installed on the front backplane work just fine. But when I tried installing drives on the rear backplane, while they would get recognized, I kept getting errors. I know it wasn't the drives because when I noticed the errors, I tried moving the same drive to the front backplane and they worked just fine. I'm pretty sure it's not the cable connecting the 9207 to the rear backplane as I had tried replacing it with a brand new cable and still got the same errors. I've tried multiple slots for the rear backplane but still get the same errors. I was able to partition the drives, but attempting to write to them kept failing.
I'm running Debian on the server and dmesg shows the following errors when the drives conk out on the rear backplane - I've edited it a bit to delete repeated lines of the same error:
[55896.254500] mpt2sas_cm0: log_info(0x31120303): originator(PL), code(0x12), sub_code(0x0303)
[55896.254546] sd 0:0:26:0: [sdz] tag#3446 FAILED Result: hostbyte=DID_SOFT_ERROR driverbyte=DRIVER_OK
[55896.254558] sd 0:0:26:0: [sdz] tag#3446 CDB: Read(16) 88 00 00 00 00 00 02 0c 96 e0 00 00 00 18 00 00
[55896.254565] blk_update_request: I/O error, dev sdz, sector 34379488 op 0x0:(READ) flags 0x80700 phys_seg 3 prio class 0
55896.255545] sd 0:0:26:0: [sdz] tag#3436 FAILED Result: hostbyte=DID_SOFT_ERROR driverbyte=DRIVER_OK
[55896.255547] sd 0:0:26:0: [sdz] tag#3436 CDB: Read(16) 88 00 00 00 00 00 02 0c 94 60 00 00 00 18 00 00
[55896.255549] blk_update_request: I/O error, dev sdz, sector 34378848 op 0x0:(READ) flags 0x80700 phys_seg 3 prio class 0
[55897.004292] sd 0:0:26:0: Power-on or device reset occurred
[55902.038356] JBD2: Detected IO errors while flushing file data on sdz1-8
[55906.255274] scsi_io_completion_action: 22 callbacks suppressed
[55906.255276] print_req_error: 22 callbacks suppressed
[55906.255282] blk_update_request: I/O error, dev sdz, sector 34481280 op 0x0:(READ) flags 0x80700 phys_seg 30 prio class 0
[55906.255286] sd 0:0:26:0: [sdz] tag#3483 FAILED Result: hostbyte=DID_SOFT_ERROR driverbyte=DRIVER_OK
[55906.255994] sd 0:0:26:0: [sdz] tag#3483 CDB: Read(16) 88 00 00 00 00 00 01 f1 14 a0 00 00 03 60 00 00
[55906.255998] blk_update_request: I/O error, dev sdz, sector 32576672 op 0x0:(READ) flags 0x80700 phys_seg 108 prio class 0
I'm at a bit of a loss as to how to further diagnose or fix the problem. I'd be very grateful for any suggestions or recommendations.
