Thank you Neil for the valuable clarification :) On Sun, Mar 14, 2010 at 12:50 AM, Neil Brown <neilb@xxxxxxx> wrote: > On Sun, 14 Mar 2010 00:31:01 +0300 > "Majed B." <majedb@xxxxxxxxx> wrote: > >> Neil, >> >> Since when was this possible? I always thought that it had to have an >> even number of disks. > > md has never imposed a 2-drive restriction on raid1. That would be fairly > pointless. > > Requiring an even number of devices would also be pointless. > > The term "mirror" is possibly a cause of confusion as it suggests an original > and a copy. It also suggests that the copy is reflected in some way. > Neither of these are true. > RAID1 stores multiple copies of the same data. All copies are equal. You can > have as many or as few of them as you like. 1, 2, 3, 4, .... > NeilBrown > > >> >> On Sun, Mar 14, 2010 at 12:26 AM, Neil Brown <neilb@xxxxxxx> wrote: >> > On Sat, 13 Mar 2010 16:06:38 -0500 >> > Carlos Mennens <carloswill@xxxxxxxxx> wrote: >> > >> >> I was told by my distributions Wiki page that Grub doesn't support >> >> RAID 5 or RAID 6 so I would need to create a volume with three disks >> >> and set the level to RAID 1: >> >> >> >> # mdadm --create /dev/md1 --level=1 --raid-devices=3 /dev/sda1 >> >> /dev/sdb1 /dev/sdc1 --spare-devices=1 /dev/sdd1 >> >> >> >> Is this possible to mirror three identical drive partitions? I was >> >> talking to some co-workers and was told that I could only pair two >> >> drives on RAID 1. >> > >> > Your co-workers are wrong, at least for md raid. With md, a RAID1 can have >> > any number of devices from 1 upwards - the limit varies in different >> > situations but is at least 28. >> > >> > Try it and see. >> > >> > NeilBrown >> > >> >> >> >> Can anyone please help me understand this? >> >> -- >> >> 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 >> > >> >> >> > > -- Majed B. -- 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
