hum, i asked this question one time, the point is: raid1 code is very easy raid10 code is more complex easy = faster, less memory, less cpu complex = faster?, more memory? more cpu? check others raid system (freebsd, netbsd) and check how they do... 2011/5/6 Keld Jørn Simonsen <keld@xxxxxxxxxx>: > On Fri, May 06, 2011 at 10:01:48AM -0400, Miles Fidelman wrote: >> Keld Jørn Simonsen wrote: >> >>As you say, RAID10,near on four disks is pretty much identical to >> >>RAID1+0 - i.e., a stripe of two normal RAID1 pairs. >> >> >> >> I don't that's exactly right. At least as I understand it: >> >> - RAID1+0 (and RAID0+1) nests things - you start with two sets of RAID1 >> mirrors, then stripe across them (or vice versa) - it's a nested set of >> steps >> >> - md RAID10 provides both mirroring and striping, but it's a more >> integrated function - (from the man page) "RAID10 provides a combination >> of RAID1 and RAID0, and sometimes known as RAID1+0. Every datablock is >> duplicated some number of times, and the resulting collection of >> datablocks are distributed over multiple drives." - but there isn't an >> inherent nesting in the process (i.e., no two disks are copies of each >> other, and md RAID10 will work over odd numbers of drives) > > Yes, you are right, RAID1+0 is nested, while Linux MD raid10 is not. > But the data layout of Linux MD RAID1+0 and Linux MD > RAID10,near is almost identical. > > keld > -- > 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 > -- Roberto Spadim Spadim Technology / SPAEmpresarial -- 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
