Hi all. I'm trying to determine best and worst case expected sequential write speeds for Linux software RAID with spinning disks. I have been assuming on the following: Best case RAID 6 sequential write speed is (N-2) * X, where is is number of drives and X is write speed of a single drive. Worst case RAID 6 sequential write speed is (N-2) * X / 2. Best case RAID 5 sequential write speed is (N-1) * X. Worst case RAID 5 sequential write speed is (N-1) * X / 2. Could someone please confirm whether these formulas are accurate or not? I am not even getting worst case write performance with an array of 12 spinning 7200 RPM SATA disks. Thus I suspect either the formulas I am using are wrong or I have alignment issues or something. My chunk size is 128 KB at the moment. Thanks, Dallas -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
