HP 418800-B21 HP StorageWorks Replication Solutions Manager 4.0.1 user guide ( - Page 156

Host volume configuration LVM and Veritas online JFS Non-LVM and Veritas online JFS LVM and VxFS without online JFS. Extend support? HP-UX 11.31 Manual (offline1 only) Policy2 and manual (online) Manual (offline1 only) Shrink support? None Policy2 and manual (online) None Non-LVM and VxFS without online JFS. VxVM HFS filesystem LVM and VxFS with or without online JFS Non-LVM and VxFS with or without online JFS VxVM HFS filesystem Manual (offline1 only) None None HP-UX 11.23 Manual3, (offline1 only) Manual (offline1 only) None None None None None None Manual (offline1 only) None None 1If the host volume is not part of a volume group, taking it offline involves unmounting it. If the host volume is part of a volume group, taking it offline involves unmounting it and deactivating the volume group. 2Policies are supported only for single virtual disk host volumes. 3Requires installation of the vgmodify tool. This tool is part of the HPUX patch PHCO_35524 for 11.23. Selecting the proper dynamic capacity policy thresholds When setting a dynamic policy, the following guidelines apply: • Use an extend threshold of 75% or greater. • Use a shrink threshold of 35% or less. • Use an increment value of approximately 10% of the current host volume size. For example, if the current size is 50 GB use an increment value of 5 GB. NOTE: Not following the above guidelines can result in a situation where the values used to set one policy may prevent you from setting the opposite policy. For example, if inappropriate values are used to set an extend policy, they may prevent you from setting a shrink policy on the same host volume. In this situation, you will be informed that the shrink policy option is not available for the selected host volume. If this situation occurs, reset the policy values using the above guidelines. When setting a dynamic capacity policy threshold, you must be aware of the interaction between the extend and shrink policy values. RSM will not allow you to select threshold values that could result in cyclic resize-a condition in which the host volume goes into a loop resizing itself. If you attempt to select a policy threshold that would result in cyclic resize, RSM alerts you and recommends a policy threshold that will avoid the situation. For example, assume you have a 1 GB host volume on which you have set a shrink policy threshold of 10% and an extend policy threshold of 50%. The desired increment size is 5 GB. When the host volume capacity reaches 0.5 GB (50% of 1 GB) the extend policy is triggered, extending the host volume size to 6 GB (1 GB + 5 GB increment). This causes the host volume capacity to drop to 8.33% , which invokes the shrink policy (