Preparing Disks for ZFS Storage Pools

Creating ZFS storage pools in Oracle Solaris 11 is similar to creating pools in Oracle Solaris 10. The following sections provide summary information about preparing disks for a ZFS root pool and non-root pools.

Review the following general pool device configuration recommendations:

Create non-root pools by using whole disks, which are easier to manage than disk slices. For example, you can easily create a mirrored storage pool with four devices as follows:
```
# zpool create tank mirror c0t1d0 c0t2d0 mirror c1t1d0 c1t2d0
```

When ZFS storage pools are created with whole disks, the disks are labeled with an EFI label rather than an SMI label. You can identify an EFI label by the lack of cylinder information in the disk label as displayed in the format utility. For example:

partition> print
Current partition table (original):
Total disk sectors available: 286478269 + 16384 (reserved sectors)

Part      Tag    Flag     First Sector         Size         Last Sector
  0        usr    wm               256      136.60GB          286478302    
  1 unassigned    wm                 0           0               0    
  2 unassigned    wm                 0           0               0    
  3 unassigned    wm                 0           0               0    
  4 unassigned    wm                 0           0               0    
  5 unassigned    wm                 0           0               0    
  6 unassigned    wm                 0           0               0    
  8   reserved    wm         286478303        8.00MB          286494686

We recommend that you create non-root pools with whole disks.

Oracle Solaris releases support advanced format disks in addition to traditional 512n disks. For more information, see Advanced Format Disk Support in Oracle Solaris 11.1 Administration: Devices and File Systems.

ZFS Root Pool Installation Improvements

Review the following installation improvements for root pools:

Disk label improvements – If the disk label or labels that are intended to contain the OS are unknown, the disks will be automatically relabeled with the appropriate disk label.

In Oracle Solaris 11.1, SPARC based systems with GPT enabled firmware and most x86 based systems are installed with an EFI (GPT) label on the root pool disk or disks.

In addition, the AI installer has improved the whole_disk keyword syntax so that if whole_disk is set to true, the disk's contents are replaced, even if it has existing partitions or slices.

AI installation of a mirrored root pool – Oracle Solaris 10 installation features allow you to create a mirrored root pool during installation.

You can use AI manifest keyword syntax to create a mirrored root pool during an Oracle Solaris 11 automatic installation. For example, the following Oracle Solaris 11.1 syntax creates a mirrored root pool using whole disks:

<!DOCTYPE auto_install SYSTEM "file:///usr/share/install/ai.dtd.1">
.
.
.
   <target>
        <disk whole_disk="true" in_zpool="rpool" in_vdev="mirrored">
        <disk_name name="c1t0d0" name_type="ctd"/>
        </disk>
        <disk whole_disk="true" in_zpool="rpool" in_vdev="mirrored">
        <disk_name name="c2t0d0" name_type="ctd"/>
        </disk>
      <logical>
        <zpool name="rpool" is_root="true">
        <vdev name="mirrored" redundancy="mirror"/>
         <!--
            Subsequent <filesystem> entries instruct an installer to create
            following ZFS datasets:

                <root_pool>/export         (mounted on /export)
                <root_pool>/export/home    (mounted on /export/home)
.
.
.       </zpool>
      </logical>
     </target>
.
.
.

ZFS Root Pool Device Requirements

In general, root pool devices are relabeled and the root pool is created when the system is installed.

Oracle Solaris 11: An SMI (VTOC) label is applied automatically to the root pool disk or disks during installation on both SPARC and x86 based systems.

# zpool status rpool
  pool: rpool
 state: ONLINE
  scan: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          c7t0d0s0  ONLINE       0     0     0

Oracle Solaris 11.1: An EFI label is applied automatically to the root pool disk or disks during installation on SPARC based systems with GPT enabled firmware and most x86 based systems. Otherwise, a VTOC disk label is installed on the root pool disk, as shown in the following example:

# zpool status rpool
  pool: rpool
 state: ONLINE
  scan: none requested
config:

        NAME      STATE     READ WRITE CKSUM
        rpool     ONLINE       0     0     0
          c7t0d0  ONLINE       0     0     0

When you attach a disk to create a mirrored root pool, use the whole disk syntax.

# zpool attach rpool c7t0d0 c7t2d0
Make sure to wait until resilver is done before rebooting.

The pool remains in a DEGRADED state until the new disk is resilvered.

# zpool status rpool
  pool: rpool
 state: DEGRADED
status: One or more devices is currently being resilvered.  The pool will
        continue to function in a degraded state.
action: Wait for the resilver to complete.
        Run 'zpool status -v' to see device specific details.
  scan: resilver in progress since Thu Jan 24 08:15:13 2013
    224M scanned out of 22.0G at 6.59M/s, 0h56m to go
    221M resilvered, 0.99% done
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       DEGRADED     0     0     0
          mirror-0  DEGRADED     0     0     0
            c7t0d0  ONLINE       0     0     0
            c7t2d0  DEGRADED     0     0     0  (resilvering)

The pool must exist either on a disk slice or on disk slices that are mirrored. If you attempt to use an unsupported pool configuration during an beadm operation, you will see a message similar to the following:
```
ERROR: ZFS pool name does not support boot environments
```
On an x86 based system, the disk must contain an Oracle Solaris fdisk partition. An Oracle Solaris fdisk partition is created automatically when the x86 based system is installed. For more information about fdisk partitions, see Guidelines for Creating an fdisk Partition in Oracle Solaris 11.1 Administration: Devices and File Systems.

For more general information about creating ZFS root pools, see ZFS Storage Pool Creation Practices.

ZFS Root Pool Disk and Boot Administration

ZFS root pool disk and boot administration summary is as follows:

Oracle Solaris 10 and Oracle Solaris 11
- SPARC: (OBP) PROM needs root pool disk with an SMI (VTOC) label.
- SPARC: If replacing a root pool disk with zpool replace, apply boot blocks manually.
```
# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c1t0d0s0
```
- SPARC and x86: Attaching a root pool disk with zpool attach to create a mirrored root pool requires the slice syntax.
```
# zpool attach rpool c0t5000CCA03C5A5314d0s0 c0t5000CCA03C5A5340d0s0
```
  If you attempt to attach a disk with an EFI label to a root pool disk that requires an SMI (VTOC) label, you will need to relabel it manually before it can be attached.
```
# format -L vtoc -d c1t0d0
Searching for disks...done
selecting c1t0d0
[disk formatted]
c1t0d0 is labeled with VTOC successfully.
```
  Be very careful that you are relabeling the correct disk because this command does no error checking. If you force an SMI (VTOC) label on a disk that is intended for the root pool, the default partition table is applied. This means that the default s0 slice size might be too small. For more information about changing partition or slice sizes, see How to Label a Disk in Oracle Solaris 11.1 Administration: Devices and File Systems.
- x86: GRUB legacy and root pool disk needs an SMI (VTOC) label.
- x86: If replacing a root pool disk with zpool replace, apply the boot blocks manually.
```
# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t0d0s0
```
- x86: Root pool disk must be less than 2 TBs.
Oracle Solaris 11.1
- SPARC: OBP requires a root pool disk with an SMI (VTOC) label.
- SPARC: If replacing a root pool disk with zpool replace, apply boot blocks manually.
```
# bootadm install-bootloader
```
- SPARC: Attaching a root pool disk with zpool attach to create a mirrored root pool requires the slice syntax.
```
# zpool attach rpool c0t5000CCA03C5A5314d0s0 c0t5000CCA03C5A5340d0s0
```
- x86: GRUB 2 and root pool disk has an EFI label in most cases.
- x86: If replacing a root pool disk with zpool replace, apply the boot blocks manually.
```
# bootadm install-bootloader
```
- x86: Attaching a root pool disk with zpool attach to create a mirrored root pool requires the whole disk syntax.
```
# zpool attach rpool c0t5000CCA03C5A5314d0 c0t5000CCA03C5A5340d0 
```
Current Oracle Solaris 10 and 11 Releases

Using the zpool attach command applies the boot blocks automatically.

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