Create Volume Group Wizard: Configure logical volumes

Use this page to create and configure one or more logical volumes that you want to include in the volume group.

You must create and configure at least one logical volume for the volume group. You can create and configure as many logical volumes as allowed by the value that you selected for the Maximum logical volumes property on the Name and configure the volume group page of this wizard.

Fields

Logical volume name
Specify a name for the logical volume that is unique to the cluster. The name you specify must consist of 1 - 32 characters. You can use alphabetic characters of A - Z and a - z, numbers of 0 - 9, and the underscore (_) character. Also, the name cannot begin with a number.
Note: If you are using this logical volume in a mirroring configuration across sites with Logical Volume Manager (LVM), include the site name as part of the logical volume name. For example, you might use a name such as LV1site1.
start of changeLogical volume typeend of change
Select the type of logical volume to create based on one of the following types of data you want to use on the logical volume:
  • Journaled file system (JFS)
  • Journaled file system 2 (JFS2)
  • System dump (sysdump)
  • Paging
  • Journaled file system log (jfslog)
  • aio_cache
  • Boot
Number of logical partitions
start of changeSpecify the minimum number of logical partitions to allocate to the logical volume. The value must be equal to, or less than, the Maximum physical partitions property that you specified on the Name and configure the volume group page of this wizard. end of change
Position on physical volume
start of changeSelect the Intraphysical Volume Allocation Policy to use for allocating physical partitions on a physical volume in the logical volume. Select a strategy that is appropriate for the type of logical volume that you are creating. The location strategy determines the length of time for seeking and accessing data on the logical volume.

Partition allocation at the center of a physical volume is a good choice for a paging space logical volume, if you expect much paging activity. Partition allocation at the beginning or the end of the physical volume is a good choice for system dump or boot logical volumes, which have infrequent use. Logical volumes that you expect to have a high level of data retrieval, or that an important application uses, are the best candidates for partition allocation closer to the center of the physical volumes.

inner_edge
outer_edge
Select one of these values to allocate physical partitions to the edges at the beginning and at the end of the physical volume. Partitions in these positions have the slowest average seek times, which generally result in longer response times for any application that uses these partitions.
inner_middle
outer_middle
Select one of these values to avoid allocating physical partitions to the edges and out of the center of the physical volume. Select either of these options to provide locations with reasonably good average seek times and to ensure that most of the partitions on a physical volume are available for allocation.
center
Select this value to allocate physical partitions to the center section of each physical volume. Partitions in this position have the fastest average seek times, which generally result in the best response time for any application that uses them. However, fewer partitions on a physical volume meet the criteria for this strategy than for any other strategy.
end of change
Range of physical volumes
Select which Interphysical Volume Allocation Policy to use for choosing physical devices to allocate the physical partitions of a logical volume:
start of changeMinimumend of change
Select this policy to use the minimum number of physical volumes for allocating the physical partitions of the logical volume.

If you select this policy, and specify a value of 1 for the Logical partition copies property, one physical volume must contain all the physical partitions of this logical volume, if possible. When a single physical volume is not possible, the minimum number is used that is consistent with other settings for the logical volume.

If you specify a value of 2 or 3 for the Logical partition copies property, this policy uses as many physical volumes as there are copies. Otherwise, all physical partitions are contained within the minimum number of physical volumes possible that is consistent with the other settings that you select.

Maximum
start of changeSelect this policy to spread the physical partitions of this logical volume over as many physical volumes as possible. This policy is a performance-oriented option, which can improve availability of the logical volume, in conjunction with the number of logical partition copies.

If not using copies, this policy might create a situation in which the logical volume becomes incomplete by losing a physical volume that contains a physical partition.

end of change
Maximum number of physical volumes
Specify the maximum number of physical volumes to be available for new allocation to the logical volume. Select a value from 1 through the total number of shared disks that you selected on the previous page of this wizard.
Interdisks allocation policy
start of changeSpecifies that the logical volume must follow a superstrict allocation policy. This policy requires that each copy of a logical partition must be on a separate physical volume. This policy ensures that partitions in one mirrored logical volume cannot share a physical volume with the partitions from another mirrored logical volume. end of change
Logical partitions copies
start of changeSpecify the number of physical partitions to be allocated to each logical partition. You can select a value of 1 - 3. The default value is 1, and does not configure any additional copies for the logical volume. A value of 2 or 3 indicates a mirrored logical volume.end of change
Mirror pool for first copy
Select the mirror pool to which to add the first copy of the logical partition.
Note: These options are available only when the Volume group type property is scalable. You also must enable mirror pools, configure them to be strict or superstrict, and define the mirror pool names on the Name and configure the volume group page of this wizard.
Mirror pool for second copy
Select the mirror pool to which you want to add the second copy of the logical partition. This option is available only when you specify a value of 2 for the Logical partition copies property.
Mirror pool for third copy
Select the mirror pool to which you want to add the third copy of the logical partition. This option is available only when you specify a value of 3 for the Logical partition copies property.

Actions

Add Another
Click Add Another to add another set of property fields so that you can configure another logical volume to include in the volume group.
Remove
Click Remove to remove a configured logical volume from the volume group and remove all content from the property fields for that logical volume.