Recreating Your Root Pool and Recovering Root Pool Snapshots

If you need to recreate your root pool and recover you root pool snapshots, the general steps are as follows:

Prepare replacement root pool disk or disks and recreate the root pool
Restore the root pool file system snapshots
Select and activate the desired boot environment
Boot the system

How to Recreate the Root Pool on the Recovery System

Review the following considerations when recovering your root pool.

If a non-redundant root pool disk fails, you will need to boot the system from installation media or an install server to either re-install the OS or restore your root pool snapshots that you archived previously.

For information about replacing a disk on your system, see your hardware documentation.
If a mirrored root pool disk fails, then you can replace the failed disk while the system is still operational. For information on replacing a failed disk in a mirrored root pool, see How to Replace a Disk in a ZFS Root Pool.

Identify and replace the failed root pool disk or system component.
This disk is generally the default boot device or you can select another disk and then reset the default boot device.
Boot the system from the Oracle Solaris 11 installation media by selecting one of the following.
- DVD or USB install media (SPARC or x86) – Insert the media and select the appropriate device as the boot device.
  
  If text-based media is used, select the Shell option from the text installer menu.
- Live media (x86 only) – The GNOME desktop session can be used during the recovery procedure.
- Automated installer or a local copy of AI media (SPARC or x86) – From the text installer menu, select the shell option. On a SPARC system, boot the AI media (either locally or over the network), and select the Shell option:
```
ok boot net:dhcp
.
.
.Welcome to the Oracle Solaris 11 installation menu 

        1  Install Oracle Solaris
        2  Install Additional Drivers
        3  Shell
        4  Terminal type (currently xterm)
        5  Reboot

Please enter a number [1]: 3
```
Prepare the root pool disk.
1. Confirm that the replacement root pool disk is visible from the format utility.
```
# format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
       0. c2t0d0 <FUJITSU-MAY2073RCSUN72G-0401 cyl 14087 alt 2 hd 24 sec 424>
          /pci@780/pci@0/pci@9/scsi@0/sd@0,0
       1. c2t1d0 <FUJITSU-MAY2073RCSUN72G-0401 cyl 14087 alt 2 hd 24 sec 424>
          /pci@780/pci@0/pci@9/scsi@0/sd@1,0
       2. c2t2d0 <SEAGATE-ST973402SSUN72G-0400-68.37GB>
          /pci@780/pci@0/pci@9/scsi@0/sd@2,0
       3. c2t3d0 <SEAGATE-ST973401LSUN72G-0556-68.37GB>
          /pci@780/pci@0/pci@9/scsi@0/sd@3,0
Specify disk (enter its number): 0
```
2. Confirm that the root pool disk has an SMI (VTOC) label and a slice 0 with the bulk of the disk space.
  Review the partition table to confirm that the root pool disk has an SMI label and a slice 0.
```
selecting c2t0d0
[disk formatted]
format> partition
partition> print
```
3. Relabel the disk with an SMI (VTOC) label, if necessary.
  Use the following shortcut commands to relabel the disk. A caution is that these commands do not provide any error checking so make sure that you are relabeling the correct disk.
  - SPARC:
```
sysA# format -L vtoc -d c2t0d0
```
    Confirm that slice 0 has disk space allocated appropriately. The default partition is applied in the above command, which might be too small for the root pool slice 0. For information about modifying the default partition table, see How to Create a Disk Slice for a ZFS Root File System in Oracle Solaris Administration: Devices and File Systems.
  - x86:
```
sysA# fdisk -B /dev/rdsk/c2t0d0p0
sysA# format -L vtoc -d c2t0d0
```
    Confirm that slice 0 has disk space allocated appropriately. The default partition is applied in the above command, which might be too small for the root pool slice 0. For information about modifying the default partition table, see How to Create a Disk Slice for a ZFS Root File System in Oracle Solaris Administration: Devices and File Systems.
Recreate the root pool.
```
sysA# zpool create rpool c2t0d0s0
```
Mount the file system that contains the snapshots from the remote system.
```
sysA# mount -F nfs sysB:/tank/snaps /mnt
```

Restore the root pool snapshots.

sysA# gzcat /mnt/rpool.snap1.gz | zfs receive -Fv rpool
receiving full stream of rpool@rpool.snap1 into rpool@rpool.snap1
received 92.7KB stream in 1 seconds (92.7KB/sec)
receiving full stream of rpool/export@rpool.snap1 into rpool/export@rpool.snap1
received 47.9KB stream in 1 seconds (47.9KB/sec)
.
.
.

Set the bootfs property.

sysA# zpool set bootfs=rpool/ROOT/solaris rpool

Recreate swap and dump devices, if necessary.
For example:
```
sysA# zfs create -V 4G rpool/swap
sysA# zfs create -V 4G rpool/dump
```
For information about sizing swap and dump volumes, see Planning for Swap Space in Oracle Solaris Administration: Devices and File Systems.
Mount the BE.
The next step requires that the BE is mounted so that the boot blocks can be installed.
```
sysA# beadm mount solaris /tmp/mnt
```

Install the boot blocks on the new disk.

SPARC:

sysA# installboot /tmp/mnt/usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c2t0d0s0

x86:

sysA# installgrub /tmp/mnt/boot/grub/stage1 /tmp/mnt/boot/grub/stage2 /dev/rdsk/c2t0d0s0

If the same devices will not be used or the devices will be configured in a different way on the original system, clear the existing device information. Then, direct the system to reconfigure the new device information.
```
# devfsadm -Cn -r /tmp/mnt
# touch /tmp/mnt/reconfigure
```
Unmount the BE.
```
#beadm unmount solaris
```

Activate the boot environment, if necessary.

For example:

sysA# beadm list
BE        Active Mountpoint Space  Policy Created          
--        ------ ---------- -----  ------ -------          
solaris-1 -      -          13.26M static 2011-09-28 15:23 
solaris   -      -          3.87G  static 2011-09-29 08:20 
# beadm activate solaris

Verify that you can boot successfully from the replacement root pool disk.
If necessary, reset the default boot device:
- SPARC: Set up the system to boot automatically from the new disk, either by using the eeprom command or the setenv command from the boot PROM.
- x86: Reconfigure the system BIOS.

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