On Fri, May 06, 2011 at 12:34:36PM -0300, Roberto Spadim wrote: > 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? I think more complex -> more intelligent, more features. I think it is actually amazing what raid10 can do. Is raid 1 in other systems really limited to say 2 disks - mirrored? Then linux raid10 is much more intelligent. > > check others raid system (freebsd, netbsd) and check how they do... Yes, and also HW raid. If Linux made raid10,far the default for RAID1, then I think Linux would compare very well with other operating systems and HW raid. Best regards keld ---- > 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
