Toby Bluhm wrote: >> With raid 10, if it happens on one of the disks in the other set, you >> don't have a problem, and if it happens to the disk in the same set >> (not very likely), > > A 1 in 3 chance of putting the two worst disks together when using 4 > disk raid10. Yes, as in a 33% chance vs a 100% chance with raid5. >> I know there is a raid10 personality for md. I saw it in the source >> code. I see people's boot logs all over the web that say this: >> >> md: linear personality registered as nr 1 >> md: raid0 personality registered as nr 2 >> md: raid1 personality registered as nr 3 >> md: raid10 personality registered as nr 9 >> md: raid5 personality registered as nr 4 >> >> Why does CentOS5 not support the raid10 personality? Do i need to >> custom compile md? Do I need to custom compile the kernel? Russ >> >> > > You have enlightened me to the raid10 module: > > [root at tikal ~]# locate raid10 > /usr/src/kernels/2.6.9-42.0.3.EL-smp-i686/include/config/md/raid10 > /usr/src/kernels/2.6.9-42.0.3.EL-smp-i686/include/config/md/raid10/module.h > > /usr/src/kernels/2.6.9-42.0.3.EL-smp-i686/include/linux/raid/raid10.h > /usr/src/kernels/2.6.9-42.0.10.EL-i686/include/config/md/raid10 > /usr/src/kernels/2.6.9-42.0.10.EL-i686/include/config/md/raid10/module.h > /usr/src/kernels/2.6.9-42.0.10.EL-i686/include/linux/raid/raid10.h > /usr/src/kernels/2.6.9-42.0.3.EL-i686/include/config/md/raid10 > /usr/src/kernels/2.6.9-42.0.3.EL-i686/include/config/md/raid10/module.h > /usr/src/kernels/2.6.9-42.0.3.EL-i686/include/linux/raid/raid10.h > /lib/modules/2.6.9-42.0.3.EL/kernel/drivers/md/raid10.ko > /lib/modules/2.6.9-42.0.10.EL/kernel/drivers/md/raid10.ko > /lib/modules/2.6.9-42.0.3.ELsmp/kernel/drivers/md/raid10.ko > > [root at tikal ~]# modprobe raid10 > > [root at tikal ~]# lsmod | grep raid > raid10 23233 0 > raid1 20033 1 > > This is not a Centos 5 machine though, it's SL4.4. > Yes, this is exactly what I'm looking to use. How would I go about enabling it on CentOS? Russ