Installing OpenBSD with softraid
[ Note that I am in the process of migrating these blog posts from Wordpress, and as such it may contain incorrect formatting, missing links, etc. My old site is available at http://www-old.perkin.org.uk/ so if you find something obviously broken please let me know. Thanks! ]
This is more of a log for me than anything else, but perhaps someone will find this useful.
OpenBSD includes a software RAID implementation which supports booting in newer snapshots, and I was itching to install the latest version and use it as my file server, which has 4 750GB disks. There is a small bit of preparation work to do prior to installing, which is the bulk of this entry, most of which is based on this undeadly.org article.
Grab latest amd64 snapshot, boot it, drop into (S)hell mode and set up the disks:
#!/bin/sh
cd /dev
sh MAKEDEV sd1 sd2 sd3 sd4 sd5
for disk in 0 1 2 3
do
# Clear beginning of disks..
dd if=/dev/zero of=/dev/rsd${disk}c bs=1m count=10
# ..and initialise new partition table
fdisk -iy sd${disk}
#
# Create BSD disklabel:
#
# - 128m partitions at start to hold kernels for booting
# - 4g spare raid on each disk for testing
# - rest raid for main OS and data
# - OS and /home on first two mirrored disks
# - /store on second two mirrored disks
#
print "a a\n\n128m\n\na d\n\n4g\nraid\na e\n\n\nraid\nw\nq\n" \
| disklabel -E sd${disk}
# Clear beginning of raid partitions
dd if=/dev/zero of=/dev/rsd${disk}d bs=1m count=10
dd if=/dev/zero of=/dev/rsd${disk}e bs=1m count=10
done
# Create RAID1 mirrors
bioctl -c 1 -l sd0e,sd1e softraid0
bioctl -c 1 -l sd2e,sd3e softraid0
# Exit shell and start the (I)nstall
exit
As for the install, go with the sensible defaults, other than:
- change keyboard layout to ‘uk’
- manually configure network, enable rtsol
- start ntpd
- do not expect to run X
When it comes to disk selection, choose sd4 as the root disk, and use the following layout:
# partition size mount
sd4a 1G /
sd4b 8G swap
sd4d 1G /tmp
sd4e 8G /var
sd4f 16G /usr
sd4h rest /home
then initialise sd5 with:
# partition size mount
sd5a 2G /altroot
sd5d 8G /scratch
sd5e rest /store
Install the full OS, set the correct timezone, then before rebooting initialize the boot partitions and copy the kernels to them. Doing this on all of them means we can boot from any disk.
#!/bin/sh
for disk in 0 1 2 3
do
newfs sd${disk}a
mount /dev/sd${disk}a /mnt2
cp /mnt/bsd* /mnt2
umount /mnt2
done
eject cd0a
reboot
Job done.