Using GMirror on FreeBSD 7.1

Submitted by sklav on Mon, 08/24/2009 - 12:46

[Allow the mounted disk (ad0) to be modified by gmirror]

This step allows the gmirror utility to modify your drive while it is mounted and is a one time operation during gmirror setup, and will not be restored on reboot.

# sysctl kern.geom.debugflags=16

[Create the mirror on ad0]

This command modifies the drive label meta-data on your hard disk so that it is recognized as a gmirror RAID disk. In the example I set gm0 but you can give it any label you like as long as you’re consistent. You will need this later to modify your /etc/fstab.