Oliver Ransom wrote: > On 31/08/2009, at 1:11 PM, Christopher Chan wrote: > > >> Miguel Medalha wrote: >> >>>> Can someone please assist met with some software RAID 1+0 setup >>>> instructions? I have searched the web, but couldn't find any. I >>>> found >>>> a lot of RAID 10 setup instructions, but it doesn't help me. >>>> >>>> >>>> >>> As Oliver Ransom replied to you, RAID 1+0 (not to be confused with >>> RAID >>> 0+1) is RAID 10. mdadm has direct support for RAID 10. I am using >>> it on >>> CentOS 5.3 and it works really well. >>> >>> >> RAID 1+0 is NOT RAID 10. raid 1+0 is achieved using the combination of >> raid1 and raid0 personalities. Raid10 is a different animal and has >> its >> own personality. (personality as reported by 'cat /proc/mdstat' aka md >> modules) >> >> raid10 was only introduced in 2.6.9 and Oliver's link clearly shows >> that >> it is 'Non-standard' or not raid1+0. >> > > RAID 10 and 1+0 are referred to interchangeably in the > Nested_RAID_levels article, "RAID 1+0, sometimes called RAID 1&0, or > RAID 10". > > I'm a bit confused now! When it comes to Linux software raid, the raid10 module does things differently from what you get from a combination of raid1 + raid0. When it comes to hardware raid, raid10 is very likely to mean raid1+0. The problem is that that chum behind the raid10 module chose a name that was not at that time strictly defined and people would use raid10 in their articles to mean raid1+0. The raid10 module can do something similar to what you get with raid1+0 but it can also do completely different things in the way it handles data. You can for example have three disks and get a 'raid10' array. You do not have to have an even number of disks to create a 'raid10' device with the raid10 module. http://neil.brown.name/blog/20040827225440 BTW, the raid10 module does not have the same reputation as the raid1 and raid0 modules...even the raid5 module did not have a good reputation five years ago sometime around when raid10 was introduced and the raid5 module has been around for some time then.