HP 418800-B21 HP StorageWorks Replication Solutions Manager 4.0.1 user guide ( - Page 158

• Can I use DC-Management with HP Business Copy EVA? You cannot use DC-Management with snapshots or mirrorclones created using HP Business Copy EVA. See Using DC-Management with replication for more information. • Can I create a snapshot or mirrorclone on a virtual disk that has a DC-Management policy set on it? No. If you set a dynamic policy on a host volume and then create a snapshot or mirrorclone on the underlying virtual disk, the policy will not execute properly. See Using DC-Management with replication for more information. • Can I manually resize a host volume that has a DC-Management policy set on it? Yes, but you should be aware of the interaction. See Using DC-Management with replication for more information. • How much can I expand a host volume? You can extend a host volume until its size reaches that of the underlying virtual disk. At that point, it is necessary to extend the size of the virtual disk to provide additional capacity to extend the file system. • How much can I shrink a host volume? The minimum size to which you can shrink a host volume is determined by the amount of data on the host volume. You cannot make a host volume too small to accommodate the data on it. • When I perform a manual extend or shrink, I can choose to extend the virtual disk or the file system. When I use a dynamic capacity policy, I don't have this choice. How does a extend or shrink policy work? When using an extend or shrink policy, the size of both the file system and the underlying virtual disk is changed when the specified threshold is reached. • Can I install more than one extend policy or shrink policy on the same host volume? No. You can only install one extend policy or shrink policy on a host volume. DC-Management best practices • When setting a dynamic policy, observe the guidelines in Selecting the proper dynamic capacity policy thresholds. • You cannot extend or shrink a file system on a write-protected disk. You can extend or shrink the underlying virtual disk on a write-protected disk. Shrinking the virtual disk in this case would enable you recover unused capacity. • Make sure you observe the guidelines when using DC-Management with replication. See Using DC-Management with replication for more information. • Make sure you have the necessary DC-Management license installed. When using DC-Management with HP Continuous Access EVA, HP recommends you install a DC-Management license on both the source and destination arrays to ensure proper operation during failover. • Use care when manually resizing a host volume on which you have set a policy. See Selecting the proper dynamic capacity policy thresholds for more information. DC-Management examples The following example presents one scenario for using DC-Management to manage storage capacity. Scenario 1 An administrator needs to create a database for the production group. The administrator doesn't know how much storage to allocate, but the request is for 200 GB. The administrator decides to allocate 100 GB initially and use DC-Management policies to resize the capacity as necessary. An extend policy is set using a threshold of 80% and an increment value of 10 GB. When the size of the database reaches 80 GB (80% of 100 GB), the DCM policy will trigger and incrementally increase the size of the host volume. The administrator also decides to set a DC-Management shrink policy to reduce the size of the host volume. This may be useful to account for periods of activity during which the database temporarily grows to a larger size. When the size of the database decreases to the set threshold, the shrink policy triggers to reduce the size of the host volume. 158 Host volumes