Encapsulating a disk

Warning:

Encapsulating a disk requires that the system be rebooted several times. Schedule performance of this procedure for a time when this does not inconvenience users.

This section describes how to encapsulate a disk for use in VxVM. Encapsulation preserves any existing data on the disk when the disk is placed under VxVM control.

A root disk can be encapsulated and brought under VxVM control. However, there are restrictions on the layout and configuration of root disks that can be encapsulated.

Use the format or fdisk commands to obtain a printout of the root disk partition table before you encapsulate a root disk. For more information, see the appropriate manual pages. You may need this information should you subsequently need to recreate the original root disk.

You cannot grow or shrink any volume (rootvol, usrvol, varvol, optvol, swapvol, and so on) that is associated with an encapsulated root disk. This is because these volumes map to physical partitions on the disk, and these partitions must be contiguous.

Disks with msdos disk labels can be encapsulated as auto:sliced disks provided that they have at least one spare primary partition that can be allocated to the public region, and one spare primary or logical partition that can be allocated to the private region.

Disks with sun disk labels can be encapsulated as auto:sliced disks provided that they have at least two spare slices that can be allocated to the public and private regions.

Extensible Firmware Interface (EFI) disks with gpt (GUID Partition Table) labels can be encapsulated as auto:sliced disks provided that they have at least two spare slices that can be allocated to the public and private regions.

The entry in the partition table for the public region does not require any additional space on the disk. Instead it is used to represent (or encapsulate) the disk space that is used by the existing partitions.

Unlike the public region, the partition for the private region requires a small amount of space at the beginning or end of the disk that does not belong to any existing partition or slice. By default, the space required for the private region is 32MB, which is rounded up to the nearest whole number of cylinders. On most modern disks, one cylinder is usually sufficient.

To encapsulate a disk for use in VxVM

  1. Before encapsulating a root disk, set the device naming scheme used by VxVM to be persistent.
    # vxddladm set namingscheme={osn|ebn} persistence=yes

    For example, to use persistent naming with enclosure-based naming:

    # vxddladm  set namingscheme=ebn persistence=yes
  2. Select Encapsulate one or more disks from the vxdiskadm main menu.

    Your system may use device names that differ from the examples shown here.

    At the following prompt, enter the disk device name for the disks to be encapsulated:

    Select disk devices to encapsulate: 
    [<pattern-list>,all,list,q,?] device name

    The pattern-list can be a single disk, or a series of disks. If pattern-list consists of multiple items, those items must be separated by white space.

    If you do not know the address (device name) of the disk to be encapsulated, enter l or list at the prompt for a complete listing of available disks.

  3. To continue the operation, enter y (or press Return) at the following prompt:
    Here is the disk selected. Output format: [Device]
    device name
      
    Continue operation? [y,n,q,?] (default: y) y
  4. Select the disk group to which the disk is to be added at the following prompt:
    You can choose to add this disk to an existing disk group or to 
    a new disk group. To create a new disk group, select a disk 
    group name that does not yet exist.
     
    Which disk group [<group>,list,q,?]
  5. At the following prompt, either press Return to accept the default disk name or enter a disk name:
    Use a default disk name for the disk? [y,n,q,?] (default: y)
  6. To continue with the operation, enter y (or press Return) at the following prompt:
    The selected disks will be encapsulated and added to the 
    disk group name disk group with default disk names.
    
    device name
    
    Continue with operation? [y,n,q,?] (default: y) y
    
  7. To confirm that encapsulation should proceed, enter y (or press Return) at the following prompt:
    The following disk has been selected for encapsulation.
     Output format: [Device]
    
    device name
    
    Continue with encapsulation? [y,n,q,?] (default: y) y

    A message similar to the following confirms that the disk is being encapsulated for use in VxVM and tells you that a reboot is needed:

    The disk device device name will be encapsulated and added to
    the disk group diskgroup with the disk name diskgroup01.
  8. For non-root disks, you can now choose whether the disk is to be formatted as a CDS disk that is portable between different operating systems, or as a non-portable sliced disk:
    Enter the desired format [cdsdisk,sliced,simple,q,?]
    (default: cdsdisk)

    Enter the format that is appropriate for your needs. In most cases, this is the default format, cdsdisk. Note that only the sliced format is suitable for use with root, boot or swap disks.

  9. At the following prompt, vxdiskadm asks if you want to use the default private region size of 65536 blocks (32MB). Press Return to confirm that you want to use the default value, or enter a different value. (The maximum value that you can specify is 524288 blocks.)
    Enter desired private region length [<privlen>,q,?]
    (default: 65536)
  10. If you entered cdsdisk as the format in step 8, you are prompted for the action to be taken if the disk cannot be converted this format:
    Do you want to use sliced as the format should cdsdisk
    fail? [y,n,q,?] (default: y)

    If you enter y, and it is not possible to encapsulate the disk as a CDS disk, it is encapsulated as a sliced disk. Otherwise, the encapsulation fails.

  11. vxdiskadm then proceeds to encapsulate the disks. You should now reboot your system at the earliest possible opportunity, for example by running this command:
    # shutdown -r now

    The /etc/fstab file is updated to include the volume devices that are used to mount any encapsulated file systems. You may need to update any other references in backup scripts, databases, or manually created swap devices. The original /etc/fstab file is saved as /etc/fstab.b4vxvm

  12. At the following prompt, indicate whether you want to encapsulate more disks (y) or return to the vxdiskadm main menu (n):
    Encapsulate other disks? [y,n,q,?] (default: n) n

    The default layout that is used to encapsulate disks can be changed.

More Information

Restrictions on using rootability with Linux

Rootability