Hi, Did you set stride/stripe configuration to filesystem that is aligned with raid configuration? Regards, Alexander On Thu, Dec 10, 2015 at 4:34 AM, Dallas Clement <dallas.a.clement@xxxxxxxxx> wrote: > 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 -- 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
