Solaris 10 5/09 Installation Guide: Planning for Installation and Upgrade

Chapter 6 ZFS Root File System Installation (Planning)

This chapter provides system requirements and limitations to assist you when you install a ZFS root pool. Also provided is an overview of the installation programs that can install a ZFS root pool.

If you have multiple boot environments on your system see Chapter 7, SPARC and x86 Based Booting (Overview and Planning) for information on booting.

Requirements for Installing a ZFS Root Pool

Table 6–1 System Requirements and Limitations


Requirement or Limitation	Description	Information
Memory	786 MB is the minimum memory. 1 GB is recommended for overall performance.	ZFS Administration Guide.
Disk space	The minimum amount of available pool space for a bootable ZFS root file system depends on the amount of physical memory, the disk space available, and the number of boot environments to be created.	For an explanation, see Disk Space Requirements for a ZFS Installation.
The ZFS storage pool must be created with slices rather than whole disks to be upgradeable and bootable.	The pool created with slices can be mirrored but not a RAID-Z or non-redundant configuration of multiple disks. The SVM device information must be already available in the `/dev/md/[r]dsk` directory. The pool must have an SMI label. An EFI-labeled disk cannot be booted. x86 only: The ZFS pool must be in a slice with an `fdisk` partition.	For information about SVM, see Overview of Solaris Volume Manager Components. For information about other restrictions for an EFI-labled disk, see Overview of Disk Management in System Administration Guide: Devices and File Systems. To create an `fdisk` partition with an SMI label, see How to Create a Solaris fdisk Partition in System Administration Guide: Devices and File Systems. For information about `fdisk` partitions, see x86: Partitioning Recommendations.
When you migrate from a UFS root (`/`) file system to a ZFS root pool with Solaris Live Upgrade, consider these requirements.	Migrating from a UFS file system to a ZFS root pool with Solaris Live Upgrade or creating a new boot environment in a root pool is new starting with the Solaris 10 10/08 release. This release contains the software needed to use Solaris Live Upgrade with ZFS. You must have at least this release installed to use ZFS with Solaris Live Upgrade. Migration is possible only from a UFS file system to a ZFS file system. File systems other than a UFS file system cannot be migrated to a ZFS root pool. A UFS file system cannot be created from a ZFS root pool. Before migrating, a ZFS storage pool must exist.	For more limitations on using Solaris Live Upgrade, see System Requirements and Limitations When Using Solaris Live Upgrade in Solaris 10 5/09 Installation Guide: Solaris Live Upgrade and Upgrade Planning. For step-by-step procedures, see Migrating a UFS File System to a ZFS File System in Solaris 10 5/09 Installation Guide: Solaris Live Upgrade and Upgrade Planning.

Disk Space Requirements for a ZFS Installation

Normally, on a system with a UFS root file system, swap and dump are on the same slice. Therefore, UFS shares the swap space with the dump device. In a ZFS root pool, swap and dump are separate zvols, so they do not share the same physical space. When a system is installed or upgraded with a ZFS root file system, the size of the swap area and the dump device are dependent on the amount of physical memory. The minimum amount of available pool space for a bootable ZFS root file system depends on the amount of physical memory, the disk space available, and the number of boot environments to be created. Approximately 1 Gbyte of memory and at least 2 Gbytes of disk space are recommended. The space is consumed as follows:

Swap area and dump device - The default size of swap is 1/2 the size of physical memory, but no less than 512 Mbytes and no greater than 2 Gbytes. The dump device is calculated based on the size of the memory and the contents of the dumpadm.conf file. This file defines what goes into a crash dump. You can adjust the sizes of your swap and device volumes before or after installation. For more information, see Introducing ZFS Properties in Solaris ZFS Administration Guide.
Boot environments - In addition to either new swap and dump space requirements or adjusted swap and dump device sizes, a ZFS boot environment that is migrated from a UFS boot environment needs approximately 6 Gbytes. Each ZFS boot environment that is cloned from another ZFS boot environment does not need additional disk space. However, the boot environment size might increase when patches are applied. All ZFS boot environments in the same root pool use the same swap and dump devices.

Solaris Installation Programs for Installing ZFS Root Pools

The following installation programs perform an initial installation of a ZFS root pool.

Solaris installation program text installer
Custom JumpStart with an installation profile

Solaris Live Upgrade can migrate a UFS file system to a ZFS root pool. Also, Solaris Live Upgrade can create ZFS boot environments that can be upgraded.

Table 6–2 ZFS Installation Programs and Limitations


ZFS Installation Program	Description	Limitations	Information
Solaris Installation program text installer	The Solaris text installer performs an initial installation for a ZFS root pool. During the installation, you can choose to install either a UFS file system or a ZFS root pool. You can set up a mirrored ZFS root pool by selecting two or more slices during the installation. Or, you can attach or add additional disks after the installation to create a mirrored ZFS root pool. Swap and dump devices on ZFS volumes are automatically created in the ZFS root pool.	The installation GUI is not available to install a ZFS root pool. You cannot create a Solaris Flash archive from a ZFS root pool. Also, you cannot install a Solaris Flash archive on a ZFS root pool. You cannot use the standard upgrade program to upgrade. You must use Solaris Live Upgrade to upgrade a ZFS root pool.	Chapter 3, Installing With the Solaris Interactive Text Installer for ZFS Root Pools (Planning and Tasks), in Solaris 10 5/09 Installation Guide: Basic Installations
Solaris Live Upgrade	You can use the Solaris Live Upgrade feature to perform the following tasks: Migrate a UFS root (`/`) file system to a ZFS root pool Create a new boot environment in the following ways: Within an existing ZFS root pool Within another ZFS root pool From a source other than the currently running system On a system with non-global zones installed After you have used the `lucreate` command to create a ZFS boot environment, you can use the other Solaris Live Upgrade commands on the boot environment.	A storage pool must be created before you use the `lucreate` command. You cannot create a Solaris Flash archive from a ZFS root pool. Also, you cannot install a Solaris Flash archive on a ZFS root pool.	Chapter 11, Solaris Live Upgrade and ZFS (Overview), in Solaris 10 5/09 Installation Guide: Solaris Live Upgrade and Upgrade Planning
JumpStart	You can create a profile to create a ZFS storage pool and designate a bootable ZFS file system. New ZFS keywords provide an initial installation.	You cannot use the `install_type upgrade` keyword to upgrade a ZFS root pool. Nor can you use the Solaris Flash keywords. Some keywords that are allowed in a UFS specific profile are not allowed in a ZFS specific profile.	For a quick reference about keywords that can be used in a ZFS installation, see Profile Keywords Quick Reference in Solaris 10 5/09 Installation Guide: Custom JumpStart and Advanced Installations. For descriptions of ZFS keywords and profile examples, see Chapter 9, Installing a ZFS Root Pool With JumpStart, in Solaris 10 5/09 Installation Guide: Custom JumpStart and Advanced Installations.