I have been testing a replacement chassis (an older supermicro 1U, SATA2) for a 4x8Tb (A,B,C,D) zfs pool. The drives are mounted in hot-swap caddies. I have tested booting from all combinations of two drives in each of the 4 (0...3) drive slots. For example (slot#/HDDid):
If I simply move either of the two HDDs to another slot then the system boots normally. For example, given
The BIOS boot sequence is
I am curious as to what might explain the effect of the slot3/slot1 configuration. Has anyone else run into something like this?
3A ,2-, 1B, 0-
; 3-,2A,1-,0B
; 3B,2C,1-,0-
; and so on. What I have discovered is that the 3x,2-,1y,0-
configuration cannot find the OS and the system will not boot. This happens for any value of x and y.If I simply move either of the two HDDs to another slot then the system boots normally. For example, given
3A ,2-, 1B, 0-
I can move 3A to 2A, or 0A, and the system boots. Likewise I can leave 3A in place and move 1B to 2B, or 0B, and the system boots. If I swap 3A with 1B the system will not boot. I can swap either or both 3A and 1B for C or D and the system still cannot find the OS. Any other configuration of two drives and the system boots normally.The BIOS boot sequence is
USB:HDD
, IDE:CDROM
, IDE:HDD0
, IDE:HDD1
, IDE:HDD2
, IDE:HDD3
. I have not tinkered with this sequence. I temporarily removed all the IDE:HDDs from the boot sequence after which the system would not boot; as expected.I am curious as to what might explain the effect of the slot3/slot1 configuration. Has anyone else run into something like this?