Does anyone know if the Dell MD1200 series controllers do "wide SAS" to the expanders? An lsiutil dump of the topology of an existing setup would be great to look at (option 16, Display attached devices)
Given that they are daisy-chain-able, I'm thinking they are using only one SAS lane instead of all four at once. (see note below).
So what that means is, max bandwidth to the drives is 6Gbps to ALL drives in unified, and 12Gbps (2x6) to all drives in split mode. Given a theoretical max of 150MB/s read/write per drive, that means even split mode would be saturated reading/writing to all 12 drives at once.
Any other RAID chassis out there that do wide SAS? I know the Supermicro ones do. But if I go Supermicro, I'll just go to the TQ backplane and direct connect each drive anyway. I already have a 16-bay Supermicro setup like that and it screams with 10 WD 3TB RE (512n) drives.
Note: I've used MD1000's that are only one SAS lane. What it appears they do to daisy-chain them is, say the SAS lanes are 0 through 3. Lane 0 goes to the EMM. The pass-through re-wires the connector to shuffle lane 1,2,3 down to 0,1,2 - so the next chassis again uses SAS lane 0, and so on. I suspect these MD1200's do too. Dell is sneaky - looking at performance tuning docs, they purposely put four MD1200s in the chain so they are using all four SAS lanes in a single cable.
Thanks in advance!
Given that they are daisy-chain-able, I'm thinking they are using only one SAS lane instead of all four at once. (see note below).
So what that means is, max bandwidth to the drives is 6Gbps to ALL drives in unified, and 12Gbps (2x6) to all drives in split mode. Given a theoretical max of 150MB/s read/write per drive, that means even split mode would be saturated reading/writing to all 12 drives at once.
Any other RAID chassis out there that do wide SAS? I know the Supermicro ones do. But if I go Supermicro, I'll just go to the TQ backplane and direct connect each drive anyway. I already have a 16-bay Supermicro setup like that and it screams with 10 WD 3TB RE (512n) drives.
Note: I've used MD1000's that are only one SAS lane. What it appears they do to daisy-chain them is, say the SAS lanes are 0 through 3. Lane 0 goes to the EMM. The pass-through re-wires the connector to shuffle lane 1,2,3 down to 0,1,2 - so the next chassis again uses SAS lane 0, and so on. I suspect these MD1200's do too. Dell is sneaky - looking at performance tuning docs, they purposely put four MD1200s in the chain so they are using all four SAS lanes in a single cable.
Thanks in advance!
