Tools for Managing Storage on HP-UX

The following tools are used to manage (or are actually pieces of) the storage stack on HP-UX – the layers of technology allowing HP-UX to write and read from mass storage devices.

Volume Managers

Volumes are logical containers that are not limited by the boundaries of the underlying physical disks on which they reside. To applications, file systems, and databases, volumes appear to be physical disks and are treated as such. HP-UX can use volumes as swap space. Volumes can contain:

File Systems
Swap Space (for paging operations)
Dump Space (for memory dump operations)
Mirror copies of other volumes
Raw disk space managed by an application such as a database manager

Volume managers allow you to group collections of physical storage (usually disk drives) and then divide the collections into logical entities called logical volumes if you are using the HP Logical Volume Manager, or simply volumes if you are using the VERITAS Volume Manager.

HP-UX 11i version 3 supports the following volume managers:

LVM

The Logical Volume Manager (LVM) is detailed in HP-UX System Administrator’s Guide: Logical Volume Management. LVM is the default volume manager for HP-UX 11i.

VxVM

The VERITAS Volume Manager (VxVM) has many features, some of which are not available with LVM or MirrorDisk/UX (the companion product to LVM that allows you to mirror data onto multiple physical disks).

The version of VxVM that ships with HP-UX is a base version containing a subset of the features offered in the full version (which requires an additional license). For complete information about which features are included with the base version and the full version of VxVM see the VERITAS Volume Manager Releases Notes corresponding to the version of the VERITAS Volume Manager you are using.

Both volume managers can co-exist on a server. Each volume manager keeps track of which disks it is controlling and any given physical disk can only be a controlled by one volume manager at a time. The utility vxvmconvert can convert an LVM volume group to a VxVM disk group if you want to migrate a disk from LVM to VxVM for greater configuration flexibility.

Volume Management Tasks

The specific volume management tasks you will need to perform will vary slightly depending on which volume manager you choose. For tasks that are common to both LVM and the VERITAS Volume Manager, the specific commands or interfaces you will need to use will also vary depending on which volume manager you are using.

Common volume management tasks include:

Volume Group / Disk Group Tasks
- Creating volume groups (from collections of physical disks)
- Adding physical disk drives to an existing volume group
- Removing physical disk drives from a volume group
- Mirroring data
Logical Volume / Volume Tasks
- Creating volumes
- Removing volumes
- Resizing volumes (and, if appropriate, the file systems within them)

In both LVM and the VERITAS Volume Manager, one volume group is treated special: the root volume group. This refers to the volume group that contains the kernel file that is used for booting the system. It is also where the root file system, the file system containing the root directory (“/”), resides. The specifics of how the root volume group is special (how it differs from other volume groups) varies depending on which volume manager you are using. Refer to the documentation for the volume manager you are using for specific information on the differences.

Tools for Managing Storage on HP-UX

Technical documentation

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Volume Managers

Volume Management Tasks