Dell DR6300 Microsoft DPM - Setting Up the DR Series System as a VTL Backup Ta - Page 49

B.3 5. Calculate the data footprint during the retention period for change rate data sets based on a 10-1 deduplication ratio 6. Calculate the ratios within the retention period for each of the data sets 7. Determine the lowest ratio data set to be retired within the retention period and create media of size that closest matches this data footprint so that when a retention period is met the most amount of media is recycled to invoke data reclamation alignment and optimizing media consumption. IMPORTANT NOTE: If other containers are being configured to host CIFS, NFS, RDA, or OST, these must also be factored into the planning and management of space. Note: For complete details, see the Dell DR Series Capacity Sizing Guide: A Dell Technical White Paper or contact a support or sales specialist for assistance. Logical VTL geometry and media sizing The logical size of the VTL, including media size and media count should be made so as to accommodate the existing data footprint targeted for protection. The calculation for such should include the initial footprint, change rate and retention period. It should also take into account the size of both full and incremental data sets. Using the smallest iteration of the data sets to dictate the logical size of the VTL media affords users the ability to retire media in smaller increments which results in high levels of use. It also provides users the ability to conduct operations across smaller objects, which results in higher levels of flexibility, such as when a restore is needed during backup operations. We can review a typical full weekly plus incremental daily example to demonstrate one method of conducting this calculation. In our example the total logical foot print for the customer environment is 20TB and with a 10% change within a weekly recovery point objective period for a complete weeks' worth of protection we calculate that we will require 22TB of total logical media to retain the data footprint for the given environment for one week. In order to allow for disparities we also include a 10% increase to allow for flexibility in the deployment and use of the VTL which results in a 24.2TB total virtual media requirement for a single weekly retention period. IMPORTANT NOTE: Media can always be added as needed. Media cannot however be deleted; therefore, care must be taken to avoid creating too many media items. In the previous example at the end of the 5-week cycle, the 1st week retires and frees up media to be reused or recycled which once processed will allow the DR to reclaim the physical space associated with the virtual media. Since the smallest data set footprint resulting from the change rate is 2TB in each incremental iteration, we create our media at 800GB increments and add as we grow. For this example the initial VTL would be created with 152 (121TB divided by 800GB) pieces of media at 800GB for each piece media. 49 Setting Up the Dell™ DR Series System as a VTL Backup Target on Microsoft® Data Protection Manager | January 2016