I am glad I asked! Thanks for all the info. Now my question next is if I am creating a 3 disk raid with a 1 disk spare, do I need to use any special 'mdadm' parameters besides what u see below for /boot (Grub)? # mdadm --create /dev/md0 --level=1 --raid-devices=3 /dev/sda1 /dev/sdb1 /dev/sdc1 --spare-devices=1 /dev/sdd1 Anything else I should add to the above command for my /boot partition? On 3/13/10, Joachim Otahal <Jou@xxxxxxx> wrote: > On Sun, Mar 14, 2010 at 12:06 AM, 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. >> >> Can anyone please help me understand this? > > /boot must be RAID1 (or a normal partition), everything else can be > RAIDwhatever. Grub has no problems reading /boot from a mirrors. > > It is possible to make RAID1 to use more than two drives and keep the all > active. In your case it is a matter of "believe" whether a spare is better > or actually using all four actively in your raid, I prefer the latter. > I have heavily tested more than two only with files via loopback yet, two > drive, three drives, four drives and more. It does work, the testfile > generated out of urandom kept the correct hash value throughout all my sick > testings. > The quick test with three SATA drives worked too, but it was just for the > fun to see whether grub pukes or works (works if you don't forget the grub > setup for drive 2, 3 etc). > My plan is: Use RAID1 with 4 drives (quad-mirroring) for /boot or / and > raid10 or raid5 for the data upon my next linux server upgrade. > > Joachim Otahal > > > -- > 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 > -- Sent from my mobile device -- 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
