I've read the previous posts about mixed SAS stacks and I am well aware of the homogeneous stack limits per shelf type
SSD (4 shelf per stack)
DS 4486 (5 shelf per stack)
Anything else (10 shelf per stack)
The DS4486 has double disks so each one uses up 2 SAS versus 1 SAS which completely explains the 5 shelf limit for Tandem shelves
So with all this well in mind I built a stack like this:
4xDS4486 (thinking ok 2 SAS per equals 8 SAS used)
I should have room for 2 more normal DS2246 with 10k drives bringing my stack to a full 10.
I built it out and when adding the last of the 2 DS2246 I received the ontap alert that the stack has 6 shelves but SHOULD only have 5...
It is almost as if having just 1 DS4486 in a stack seems to make the system think EVERY shelf in that stack is a tandem and primitivley applies the 5 tandem shelf limit
It seems to me I would get the same error with a stack built like this:
1 DS4486 with only 7k
5 DS2246 with only 10k
Is there anyway to bypass this limit? Is it a hard limit? Meaning in spite of the alert could I still use that last DS2246's 10k disks? (The 6th shelf)
I went ahead and removed the last DS2246 so now I just have the 4xDS4486 and 1xDS2246...
I have zero qualms running 4xDS4486 with 7k and 2xDS2246 with 10k and it should calculate to a limit of 10 SAS ID's( 2x4=8 + 1x2=2 ==10)
Appreciate any insight by those with experience in these matters
FAS8040a HA pair running 8.2.5p5 7mode