This is the man md about: When 'near' replicas are chosen, the multiple copies of a given chunk are laid out consecutively across the stripes of the array, so the two copies of a datablock will likely be at the same offset on two adjacent devices. I think the word "similar" is the same. ------------------ kedacomkernel 2012-04-16 ------------------------------------------------------------- 发件人:NeilBrown 发送日期:2012-04-16 13:41:33 收件人:kedacomkernel 抄送:linux-raid 主题:Re: question about raid10 near copy info in man mdadm. On Mon, 16 Apr 2012 13:28:14 +0800 "kedacomkernel" <kedacomkernel@xxxxxxxxx> wrote: > Hi: > I readed the information about raid10 near copy in man mdadm. > It is: > 'n' signals 'near' copies. Multiple copies of one data block are at similar offsets in different > devices. > But I think this wrong. > If raid10 had five disks and near copy is equal three. > The layout like: > 5 disks > -------------------- > A1 A1 A1 A2 A2 > A2 A3 A3 A3 A4 > > But the copies of datablock A2 are not at similar offset in different device. > They are certainly on different devices so I guess you are questioning the use of the word "similar". What do you understand "similar" to mean? How would you describe offsets which might be the same, or might differ by one chunk-size? I'm happy to change the text if it is confusing, but only if the result is undoubtedly less confusing. NeilBrown ?韬{.n?????%??檩??w?{.n???{炳盯w???塄}?财??j:+v??????2??璀??摺?囤??z夸z罐?+?????w棹f