I have a Netapp DS4243 with a Dell Xyratex Compellant HB1235 controller in (basically IOM6).
If I put an IOM12 controller in, I get SAS12 instead of SAS6, but if the drives are all SATA6 or SAS6, do I actually gain anything?
E.g., the bandwidth from HBA to controller is now 12Gb/channel, with a 4 channel link, but does it actually run at that between the HBA and the controller, or does it run at the speed of the drives?
Obviously I'm never going to get >6gb/s from a single drive, but say I'm reading from 8 drives at once. Are they fine because 8x6 = 4x12, or are they throttled because it can't run at 12 and 8x6 > 4x6?
If I put an IOM12 controller in, I get SAS12 instead of SAS6, but if the drives are all SATA6 or SAS6, do I actually gain anything?
E.g., the bandwidth from HBA to controller is now 12Gb/channel, with a 4 channel link, but does it actually run at that between the HBA and the controller, or does it run at the speed of the drives?
Obviously I'm never going to get >6gb/s from a single drive, but say I'm reading from 8 drives at once. Are they fine because 8x6 = 4x12, or are they throttled because it can't run at 12 and 8x6 > 4x6?