Placing Disks Under VxVM Control

When you add a disk to a system that is running VxVM, you need to put the disk under VxVM control so that VxVM can control the space allocation on the disk. Unless you specify a disk group, VxVM places new disks in a default disk group according to the rules given in Rules for Determining the Default Disk Group.

The method by which you place a disk under VxVM control depends on the circumstances:

• If the disk is new, it must be initialized and placed under VxVM control. You can use the menu-based vxdiskadm utility to do this.

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 Caution    Initialization destroys existing data on disks.

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• If the disk is not needed immediately, it can be initialized (but not added to a disk group) and reserved for future use. To do this, enter none when asked to name a disk group. Do not confuse this type of "spare disk" with a hot-relocation spare disk.
• If the disk was previously initialized for future use by VxVM, it can be reinitialized and placed under VxVM control.
• If the disk was previously used for a file system, VxVM prompts you to confirm that you really want to destroy the file system.
• If the disk was previously in use by the LVM subsystem, you can preserve existing data while still letting VxVM take control of the disk. This is accomplished using conversion. With conversion, the virtual layout of the data is fully converted to VxVM control (see the VERITAS Volume Manager Migration Guide).
• If the disk was previously in use by the LVM subsystem, but you do not want to preserve the data on it, use the LVM command, pvremove, before attempting to initialize the disk for VxVM.
• Multiple disks on one or more controllers can be placed under VxVM control simultaneously. Depending on the circumstances, all of the disks may not be processed the same way.

It is possible to configure the vxdiskadm utility not to list certain disks or controllers as being available. For example, this may be useful in a SAN environment where disk enclosures are visible to a number of separate systems.

To exclude a device from the view of VxVM, select item 16 (Prevent multipathing/Suppress devices from VxVM's view) from the vxdiskadm main menu. See Disabling and Enabling Multipathing for Specific Devices for details.