Managing ZFS File Systems in Oracle® Solaris 11.2

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Updated: December 2014

Managing Your ZFS Swap and Dump Devices

During the installation process, a swap area is created on a ZFS volume in the ZFS root pool. For example:

# swap -l
swapfile                   dev    swaplo   blocks     free
/dev/zvol/dsk/rpool/swap 145,2        16 16646128 16646128

During the installation process, a dump device is created on a ZFS volume in the ZFS root pool. In general, a dump device requires no administration because it is set up automatically at installation time. For example:

# dumpadm
Dump content: kernel pages
Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash/
Savecore enabled: yes
Save compressed: on

If you disable and remove the dump device, then you will need to enable it with the dumpadm command after it is recreated. In most cases, you will only have to adjust the size of the dump device by using the zfs command.

For information about the swap and dump volume sizes that are created by the installation programs, see Identifying ZFS Root Pool Requirements.

Both the swap volume size and the dump volume size can be adjusted after installation. For more information, see Adjusting the Sizes of Your ZFS Swap and Dump Devices.

Consider the following issues when working with ZFS swap and dump devices:

  • If you want to create swap and dump devices in a non-root pool, do not create swap and dump volumes in a RAID-Z pool. If a pool includes swap and dump volumes, it must be a one-disk pool or a mirrored pool. Otherwise, you will see a message similar to the following:

    /dev/zvol/dsk/rzpool/swap: Operation not supported
  • Create a swap or dump volume in a non-root pool. Running the dumpadm –d command resets the dump device.

    # zfs create -V 10g bpool/dump2
    # dumpadm -d /dev/zvol/dsk/bpool/dump2
    Dump content      : kernel with ZFS metadata
    Dump device       : /dev/zvol/dsk/bpool/dump2 (dedicated)
    Savecore directory: /var/crash
    Savecore enabled  : yes
    Save compressed   : on
  • Separate ZFS volumes must be used for the swap area and dump devices.

  • Sparse volumes are not supported for swap volumes.

  • Currently, using a swap file on a ZFS file system is not supported.

  • If you need to change your swap area or dump device after the system is installed, use the swap and dumpadm commands as in previous Solaris releases. For more information, see Chapter 3, Configuring Additional Swap Space, in Managing File Systems in Oracle Solaris 11.2 and Troubleshooting System Administration Issues in Oracle Solaris 11.2 .