Creating a system RAID-10 device
Joan Picanyol i Puig
pica at biaix.org
Wed Jan 18 04:51:24 PST 2006
* Sven Willenberger <sven at dmv.com> [20060117 22:06]:
> over 3 mirror raid arrays that would encompass the entire filesystem
> including the /boot and root partitions.
> Generally I would create a RAID10 from 6 disks as follows:
> gmirror label -v -b round-robin md1 da0 da1
> gmirror label -v -b round-robin md2 da2 da3
> gmirror label -v -b round-robin md3 da4 da5
> gstripe label -v -s 131072
> md0 /dev/mirror/md1 /dev/mirror/md2 /dev/mirror/md3
> newfs /dev/stripe/md0
> naturally the problem here is that it cannot be done on a system that
> booted from da0. I have seen the example of setting up a mirrored system
> (http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html )
> which won't quite work for my case either. Using this method I could
> probably get the one mirror (md1) to work, but I know of no way of then
> adding the other 2 mirror sets and then redoing the system to stripe
> across all 3 mirrored sets.
Uhm. The problem is that you can't mount the root fs from a striped
partition. Create an extra slice on each drive and either configure a
6-way mirror or a mirror-of-3-sripes to boot from.
> The only thing I could think of was to boot from the livecd and create
> the 6-disk array and then trying to install FreeBSD onto this
> filesystem. In order to do this the installer would have to
> recognize /dev/stripe/md0 as a valid "drive" -- is there any way to have
> this happen?
I don't believe sysinstall is smart enough, but you can always use the
install.sh scripts on the distribution. However, the above still aplies.
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