Managing ZFS File Systems in Oracle® Solaris 11.2

Exit Print View

Updated: December 2014

Identifying ZFS Root Pool Requirements

Review the following sections that describe ZFS root pool space and configuration requirements.

ZFS Root Pool Space Requirements

When a system is installed, the size of the swap volume and the dump volume are dependent upon the amount of physical memory. The minimum amount of pool space for a bootable ZFS root file system depends upon the amount of physical memory, the disk space available, and the number of boot environments (BEs) to be created.

Review the following ZFS storage pool space requirements:

  • For a description of memory requirements for the different installation methods, see Oracle Solaris 11.2 Release Notes.

  • At least 7-13 GB of disk space is recommended. The space is consumed as follows:

    • Swap area and dump device – The default sizes of the swap and dump volumes that are created by the Solaris installation programs vary based on the amount of memory on the system and other variables. The dump device size is approximately half the size of physical memory or greater, depending on the system's activity.

      You can adjust the sizes of your swap and dump volumes to sizes of your choosing as long as the new sizes support system operation, during or after installation. For more information, see Adjusting the Sizes of Your ZFS Swap and Dump Devices.

    • Boot environment (BE) – A ZFS BE is approximately 4-6 GB. Each ZFS BE that is cloned from another ZFS BE doesn't need additional disk space. Consider that BE size will increase when the BE is updated, depending on the updates. All ZFS BEs in the same root pool use the same swap and dump devices.

    • Oracle Solaris OS Components – All subdirectories of the root file system that are part of the OS image, with the exception of /var, must be in the root file system. In addition, all Solaris OS components must reside in the root pool with the exception of the swap and dump devices.

ZFS Root Pool Configuration Requirements

Review the following ZFS storage pool configuration requirements:

  • The disk that is intended for the root pool can have either an EFI (GPT) on a SPARC based system with GPT aware firmware or an x86 based system, in most cases. Or, an SMI (VTOC) label is applied on a SPARC system without GPT aware firmware. For information about the EFI (GPT) label, see Using Disks in a ZFS Storage Pool.

  • The pool must exist either on a disk slice or on disk slices that are mirrored if an SMI (VTOC) label disk exists. Or, if the root pool disks are EFI (GPT) labeled, the pool can exist on a whole disk or mirrored whole disks. If you attempt to use an unsupported pool configuration during a beadm operation, you will see a message similar to the following:

    ERROR: ZFS pool name does not support boot environments

    For a detailed description of supported ZFS root pool configurations, see Creating a ZFS Root Pool.

  • On an x86 based system, the disk must contain a Solaris fdisk partition. A Solaris fdisk partition is created automatically when the x86 based system is installed. For more information about Solaris fdisk partitions, see Using the fdisk Option in Managing Devices in Oracle Solaris 11.2 .

  • Pool properties or file system properties can be set on a root pool during an automatic installation. The gzip compression algorithm is not supported on root pools.

  • Do not rename the root pool after it is created by an initial installation. Renaming the root pool might cause an unbootable system.

  • Do not use a thinly-provisioned VMware device for a root pool device.