I'm trying to get my head around how a multi lane x4 SAS connector works in a DAS system such as the Dell MD1000. I understand that each lane is 3Gbps, and that multiple hard drives can share a lane. What I'm having trouble finding information on is how are drives assigned to a lane, and how does that change when you daisy chain two additional md1000's to another md1000?
That's 15 disks per shelf and a total of 45 disks in a three shelf configuration. This would be in a single path configuration BTW, meaning one x4 SAS cable.
All, first thanks for all the help, but I think you're all heading down a slightly different path than what I'm asking. I get the whole thorughput saturation, that wasn't my question. I know what the theoretical max is simply based on the fact that the server has a single 12g conection per array of shelves. Meaning Server >>>>12g>>>>MD10001>>>>>MD10002>>>>>MD10003 is going to be 12g as it all depends on the servers single connection and each md1000 is daisy chained with a 12Gbps link.
My question is simply if there are 15 drives per shelf and 3 shelves, how do i know which drives go on which lane of a given 4x connector? While it's likely not to matter in the end, i was merely curious.
Also FYI, the enclosure is SAS, but the drives are SATA.