SPARC: How to Create a Mirror From root (/) (Command Line)

Use this task to mirror root (/) on a SPARC system.

The task for using the command line to mirror root (/) on an x86 system is different from the task used for a SPARC system. To mirror root (/) on an x86 system, refer to "x86: How to Create a Mirror From root (/) (Command Line)". When mirroring root (/), it is essential that you record the secondary root slice name to reboot the system if the primary submirror fails. This information should be written down, not recorded on the system, which may not be available. See Chapter 7, Troubleshooting the System for details on recording the alternate boot device, and on booting from the alternate boot device.

The high-level steps in this procedure are:

• Using metainit(1M) -f to put the root (/) slice in a single slice (one-way) concat (submirror1)

• Creating a second concat (submirror2)

• Using metainit(1M) to create a one-way mirror with submirror1

• Running the metaroot(1M) command

• Running the lockfs(1M) command

• Rebooting

• Using metattach(1M) to attach submirror2

• Recording the alternate boot path

Make sure you have met the prerequisites ("Prerequisites for Creating DiskSuite Objects"), and have read the preliminary information ("Preliminary Information for Creating Mirrors"). For more information refer to the metainit(1M), metaroot(1M), and metattach(1M) man pages.

Example -- SPARC: Creating a Mirror From root (/)

# metainit -f d11 1 1 c0t3d0s0
d11: Concat/Stripe is setup
# metainit d12 1 1 c1t3d0s0
d12: Concat/Stripe is setup
# metainit d10 -m d11
d10: Mirror is setup
# metaroot d10
# lockfs -fa
# reboot
...
# metattach d10 d12
d10: Submirror d12 is attached
# ls -l /dev/rdsk/c1t3d0s0
lrwxrwxrwx   1 root     root          88 Feb  8 15:51 /dev/rdsk/c1t3d0s0 ->
../../devices/iommu@f,e0000000/vme@f,df010000/SUNW,pn@4d,1080000/ipi3sc@0,0/i
d@3,0:a,raw

The -f option forces the creation of the first concatenation, d11, which contains the mounted file system root (/) on /dev/dsk/c0t3d0s0. The second concatenation, d12, is created from /dev/dsk/c1t3d0s0. (This slice must be the same size or greater than that of d11.) The metainit command with the -m option creates the one-way mirror d10 using the concatenation containing root (/). Next, the metaroot command edits the /etc/vfstab and /etc/system files so that the system may be booted with the root file system (/) on a metadevice. (It is a good idea to run lockfs -fa before rebooting.) After a reboot, the submirror d12 is attached to the mirror, causing a mirror resync. (The system verifies that the concatenations and the mirror are set up, and that submirror d12 is attached.) The ls -l command is run on the root raw device to determine the path to the alternate root device in case the system needs to be booted from it.