Here you go..
This is for Solaris 10.

Description:
Sun has recently released x86 and x64 platforms, which have inbuilt SCSI/Serial
Attached SCSI(SAS) RAID controllers.

It is recommended to use Hardware RAID controllers for the Root disk mirror,
for performance and reliability reasons.

But, Solaris[TM] Operating System(OS) also gives the flexibility to mirror the
root disk using Solaris[TM] Volume Manager(SVM), in Solaris 10 OS.

Document Body:
This document provides the step-by-step procedure, to install and maintain the
Solaris Volume Manager, in a Solaris 10 OS for x86 Platforms environment for
Sun Fire[TM] x64 platforms.

NOTE: This root mirroring procedure for Solaris Volume Manager is tested, and is
only recommended, with Solaris 10 OS for x86 Update 1 (1/06) release or later.

Previous releases of Solaris 10 OS for x86 release had some problems
which are fixed in update1. So it is recommended to use Solaris 10U1 if
customer's intend to use SVM[TM] for root mirroring.

Following, is a list of servers, on which this procedure can be used:

Sun Fire[TM] V20z / Sun Fire V40z
Sun Fire x4100 / Sun Fire x4200
Sun Fire x2100

Note: In the above list of servers, Sun Fire x2100 uses an nVidia RAID
controller. Solaris OS doesn't support the nVidia driver as of now, so Solaris
Volume Manager is the only option for mirroring the root disk.

Step by Step procedure for SVM root mirroring:
Root and mirror disks, are here referred to as primary and secondary disks respectively.

1. In this step, you will need to boot cdrom in single user mode off the Solaris media or network. [refer to info doc 21310 for cdrom boot in single user mode and 13267 for info doc on fdisk] [refer to info doc 84167 for pxe boot in Solaris 10] You will need to initialize each disk prior to installation and or mirroring.

In order to initialize any new X86 disk, you need to run fdisk prior to mirroring and or installation. It is recommended to delete the current layout and then create the new partition as follows. I am using c1t1d0s2 in this case but that will vary according to your system and format output.

1.
fdisk /dev/rdsk/c1t0d0s2
WARNING: Device /dev/rdsk/c1t0d0s2:
The device does not appear to include absolute
sector 0 of the PHYSICAL disk (the normal location for an fdisk table).
Fdisk is normally used with the device that represents the entire fixed disk.
(For example, /dev/rdsk/c0d0p0 on x86 or /dev/rdsk/c0t5d0s2 on sparc).
Are you sure you want to continue? (y/n) y

Total disk size is 8924 cylinders
Cylinder size is 16065 (512 byte) blocks
Cylinders
Partition Status Type Start End Length %
========= ====== ============ ===== === ====== ===
1 Active Solaris2 0 365 366 4
2 Diagnostic 365 366 2 0


SELECT ONE OF THE FOLLOWING:
1. Create a partition
2. Specify the active partition
3. Delete a partition
4. Change between Solaris and Solaris2 Partition IDs
5. Exit (update disk configuration and exit)
6. Cancel (exit without updating disk configuration)
Enter Selection: 3
Specify the partition number to delete (or enter 0 to exit): 1
Are you sure you want to delete partition 1? This will make all files and
programs in this partition inaccessible (type "y" or "n"). y
Partition 1 has been deleted. This was the active partition.1

Total disk size is 8924 cylinders
Cylinder size is 16065 (512 byte) blocks
Cylinders
Partition Status Type Start End Length %
========= ====== ============ ===== === ====== ===
1 Diagnostic 365 366 2 0


SELECT ONE OF THE FOLLOWING:
1. Create a partition
2. Specify the active partition
3. Delete a partition
4. Change between Solaris and Solaris2 Partition IDs
5. Exit (update disk configuration and exit)
6. Cancel (exit without updating disk configuration)
Enter Selection: 3
Specify the partition number to delete (or enter 0 to exit): 1
Are you sure you want to delete partition 1? This will make all files and
programs in this partition inaccessible (type "y" or "n"). y
Partition 1 has been deleted.1
Total disk size is 8924 cylinders
Cylinder size is 16065 (512 byte) blocks
Cylinders

Partition Status Type Start End Length %
========= ====== ============ ===== === ====== ===

WARNING: no partitions are defined!
SELECT ONE OF THE FOLLOWING:
1. Create a partition
2. Specify the active partition
3. Delete a partition
4. Change between Solaris and Solaris2 Partition IDs
5. Exit (update disk configuration and exit)
6. Cancel (exit without updating disk configuration)
Enter Selection: 1
Select the partition type to create:
1=SOLARIS2 2=UNIX 3=PCIXOS 4=Other
5=DOS12 6=DOS16 7=DOSEXT 8=DOSBIG
9=DOS16LBA A=x86 Boot B=Diagnostic C=FAT32
D=FAT32LBA E=DOSEXTLBA F=EFI 0=Exit? 1
Specify the percentage of disk to use for this partition[1]
(or type "c" to specify the size in cylinders). c
Enter starting cylinder number: 1
Enter partition size in cylinders: 8000
Should this become the active partition? If yes, it will be activated
each time the computer is reset or turned on.
Please type "y" or "n". y
Partition 1 is now the active partition.1
Total disk size is 8924 cylinders
Cylinder size is 16065 (512 byte) blocks
Cylinders
Partition Status Type Start End Length %
========= ====== ============ ===== === ====== ===
1 Active Solaris2 1 8000 8000 90

SELECT ONE OF THE FOLLOWING:
1. Create a partition
2. Specify the active partition
3. Delete a partition
4. Change between Solaris and Solaris2 Partition IDs
5. Exit (update disk configuration and exit)
6. Cancel (exit without updating disk configuration)
Enter Selection: 1
Select the partition type to create:
1=SOLARIS2 2=UNIX 3=PCIXOS 4=Other
5=DOS12 6=DOS16 7=DOSEXT 8=DOSBIG
9=DOS16LBA A=x86 Boot B=Diagnostic C=FAT32
D=FAT32LBA E=DOSEXTLBA F=EFI 0=Exit? B
Specify the percentage of disk to use for this partition
(or type "c" to specify the size in cylinders). c
Enter starting cylinder number: 8001
Enter partition size in cylinders: 924
Total disk size is 8924 cylinders
Cylinder size is 16065 (512 byte) blocks

Should this become the active partition? If yes, it will be activated
each time the computer is reset or turned on.
Please type "y" or "n". n
Total disk size is 8924 cylinders
Cylinder size is 16065 (512 byte) blocks
Cylinders
Partition Status Type Start End Length %
========= ====== ============ ===== === ====== ===
1 Active Solaris2 1 8000 8000 90
2 Diagnostic 8001 8919 919 10

SELECT ONE OF THE FOLLOWING:
1. Create a partition
2. Specify the active partition
3. Delete a partition
4. Change between Solaris and Solaris2 Partition IDs
5. Exit (update disk configuration and exit)
6. Cancel (exit without updating disk configuration)
Enter Selection: 5
#
Please note if the disk geometry of the x86 is different you will need to match this in disk labeling under format and in fdisk.
print disk 0
Volume:
Current partition table (original):
Total disk cylinders available: 15940 + 2 (reserved cylinders)
Part Tag Flag Cylinders Size Blocks
0 root wm 518 - 15581 17.44GB (15064/0/0) 36575392
1 swap wu 1 - 432 512.16MB (432/0/0) 1048896
2 backup wm 0 - 15939 18.45GB (15940/0/0) 38702320
3 unassigned wm 433 - 517 100.77MB (85/0/0) 206380
4 unassigned wu 0 0 (0/0/0) 0
5 unassigned wu 0 0 (0/0/0) 0
6 unassigned wu 0 0 (0/0/0) 0
7 unassigned wu 0 0 (0/0/0) 0
8 boot wu 0 - 0 1.19MB (1/0/0) 2428
9 unassigned wu 0 0 (0/0/0) 0

print disk 1
Current partition table (original):
Total disk cylinders available: 2548 + 2 (reserved cylinders)
Part Tag Flag Cylinders Size Blocks
0 root wm 129 - 2404 17.44GB (2276/0/0) 36563940
1 swap wu 1 - 128 1004.06MB (128/0/0) 2056320
2 backup wm 0 - 2547 19.52GB (2548/0/0) 40933620
3 unassigned wm 2405 - 2417 101.98MB (13/0/0) 208845
4 unassigned wm 0 0 (0/0/0) 0
5 unassigned wm 0 0 (0/0/0) 0
6 unassigned wm 0 0 (0/0/0) 0
7 unassigned wm 0 0 (0/0/0) 0
8 boot wu 0 - 0 7.84MB (1/0/0) 16065
9 unassigned wm 0 0 (0/0/0) 0

You will have to layout your disks in format to label them with the same disk geometry as shown above but varied according to your specifications. It is recommended that the primary disk should be the smaller of the two disks per Bugid 6225636.

2. Check for the latest Solaris 10 x86 SVM patches. Check for the latest patch

3. Create one slice(preferably Slice 3) of 100MB(minimum recommended) on
the primary disk, for storing the metadb replicas.

4. After creating the slice for metadb replicas, copy the VTOC of the primary
disk to the secondary disk, so the same slice information is copied to the
secondary disk.(In the examples. c1t0d0 is primary and c1t1d0 is secondary
disk)

For example: # prtvtoc /dev/rdsk/c1t0d0s2 | fmthard -s - /dev/rdsk/c1t1d0s2

5. Create metadb replicas in slice 3 of both primary and secondary disks.

For example: # metadb -afc 3 c1t0d0s3 c1t1d0s3

6. Create metadevices for /, swap, and /export/home file systems. Create
meta-devices for any other filesystems that are part of the primary disk.

For example:
# metainit -f d10 1 1 c1t0d0s0 --->
This creates metadevice d10 for root slice of primary disk.
# metainit d20 1 1 c1t1d0s0
This creates metadevice d20 for root slice of secondary disk.
# metainit d0 -m d10
creating a one way mirror using d10.

In the same way create, metadevices for other file systems, including swap.

7. Update the /etc/vfstab file, with the metadevices for the file systems.

Example: metaroot d0
--> This command will update vfstab - /dev/md/dsk/d0 as / filesystem.
For other filesystems and swap, manually edit the vfstab
entries.

8. reboot the system.

9. Once the system has booted, check with either the "df" or "mount" command,
to check whether the file systems are using metadevices.

10. Attach the second part of the mirror to the meta mirrors.

Example: # metattach d0 d20

This will attach metadevice d20 to d0.
After this command, mirror resync will start.

11. Once all file systems are attached, check all the metadevice status are
"Okay". Then, update the secondary disk bootable using an installgrub
command.

Note: From Solaris 10 x86 U1, the installboot command is obselete. So, use the
installgrub command, to make the second disk bootable. It is better to
run this command once, to make sure the secondary disk is bootable.

Example: # installgrub -fm /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t1d0s0

The installgrub utility will update the Master Boot record of the
secondary disk, so that it can be bootable.

12. Now update the secondary disk as alternate bootpath in /boot/solaris/bootenv.rc file.
(This can be done by executing the eeprom command)

Example: eeprom altbootpath="<secondary boot disk path>"

It is important to add this altbootpath to the bootenv.rc for successful mirroring.

13. Now the system can be safely rebooted, to check if it is booting with
root disk mirrored.


Recovering from primary boot disk failure:

If the primary root disk fails, the system will continue to run from the
secondary boot disk. There will be SCSI errors on the console, about the disk
failure.

"Primary root disk can be replaced online without bringing down the system"


Note: It is not necessary to remove the failed disk using the cfgadm or devfsadm
commands. If a new disk is installed in place of the failed disk, just
execute the devfsadm command, so that the OS can recognize the new disk.
Then the "format" command will show the new disk. If the new installed
disk installed has no fdisk partition, then create the fdisk partition
from the format program, so that the new disk can be used for mirroring.

Step-by-Step Procedure for replacing a failed disk:

1. Insert the new disk in place of the failed disk. Create the whole disk for
Solaris partition.

2. copy the VTOC of the secondary disk to the primary disk.
Example: prtvtoc /dev/rdsk/c1t1d0s2 | fmthard -s - /dev/rdsk/c1t0d0s2

3. Then re-attach the failed mirrors using the metareplace command.
Example: metareplace -e d0 < new disk >

Once the resynchronisation has completed, the primary disk is successfully
mirrored back online.

NOTE: The above procedure can be followed for replacing a secondary disk
failure.