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Encapsulating a disk

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.

See "Rootability" on page 109.

See "Restrictions on using rootability with Linux" on page 109.

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. Select menu item 2 (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:

Encapsulate one or more disks

Menu: VolumeManager/Disk/Encapsulate

Use this operation to convert one or more disks to use the

Volume Manager. This adds the disks to a disk group and

replaces existing partitions with volumes. Disk encapsulation

requires a reboot for the changes to take effect.

More than one disk or pattern may be entered at the prompt.

Here are some disk selection examples:

sda: add only disk sda

sdb hdc: add both disk sdb and hdc

xyz_0: a single disk (in the enclosure-based naming

scheme)

xyz_: all disks on the enclosure whose name is xyz

Select disk devices to encapsulate:

[<pattern-list>,all,list,q,?] device name

Where <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.

2. 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

3. Select the disk group to which the disk it 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,?]

4. 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)

5. To continue with the operation, enter y (or press Return) at the following prompt:

   The selected disks will be encapsulated and added to the

   diskgroup disk group with default disk names.

   device name

   Continue with operation? [y,n,q,?] (default: y) y

6. 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 mydg01.

7. 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. However, only the sliced format is suitable for use with root, boot or swap disks.

8. 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)

9. If you entered cdsdisk as the format in step 7, 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.

10. vxdiskadm then proceeds to encapsulate the disks.

    VxVM NOTICE V-5-2-311 The device name disk has been configured

    for encapsulation.

    VxVM INFO V-5-2-340 The first stage of encapsulation has

    completed successfully.

    You should now reboot your system at the earliest possible

    opportunity.

The encapsulation will require two or three reboots which

will happen automatically after the next reboot. To reboot

execute the command:

shutdown -r now

This will update the /etc/fstab file so that volume devices

are used to mount the file systems on this disk device. You

will need to update any other references such as backup

scripts, databases, or manually created swap devices.

The original /etc/fstab file is saved as /etc/fstab.prevm.

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.

See "Displaying or changing default disk layout attributes" on page 96.