HP StorageWorks 6000 HP StorageWorks VLS and D2D Solutions Guide (AG306-96028, - Page 60

• Overwrite vs. append: Overwriting and appending to cartridges is also where virtual tape has an advantage. With physical media you may want to append multiple backup jobs to a single cartridge in order to reduce media costs; the downside is that cartridges cannot be overwritten until the retention policy for the last backup on that cartridge has expired. With virtual tape, you can configure a large number of cartridges for "free" and you can configure their sizes appropriately to the amount of data stored in a specific backup. Therefore, appended backups provide no benefit. (This does not apply to VLS deduplication where appending is required to fill up tapes and perform space reclamation on them.) Considering the above factors, the following provides an example of a good rotation scheme. This user requires weekly full backups sent offsite and recovery point objectives of every day in the last week, every week in the last month, every month in the last year, and every year in the last five years: • Four daily backup cartridges, Monday to Thursday, incremental backup, overwritten every week. • Four weekly backup cartridges, on Fridays, full backup, overwritten every fifth week. • 12 monthly backup cartridges, last Friday of the month, overwritten every 13th month. • Five yearly backup cartridges, last day of the year, overwritten every five years. In the steady state daily backups will be small, and while they will always overwrite the last week the amount of data overwritten will be small. Weekly full backups will always overwrite, but housekeeping has plenty of time to run over the following day or weekend; the same is true for monthly and yearly backups. The user can also offload a full backup to physical tape every week, month, and year after the full backup runs for offsite storage. D2D Blueprints The following blueprints of D2D virtual tape libraries with deduplication and replication start from specifying company requirements, then defining the HP blueprint for the solution, and finally defining any solution caveats or ISV dependencies associated with the solution. This will help you make informed decisions and allow you to quickly assess areas of concern and possible implementations. Single Site Cost Effective Backup Device Consolidation Company requirements: small site with fewer than 6 servers, fewer than 5 TB, no SAN, wants a single device for backup that can grow with the business. Solution: HP D2D Backup System (iSCSI) with Tape Offload, typically used with HP Data Protector Express or Symantec Backup Exec Caveats: The smaller D2D units shown here are a fixed size and not directly expandable in capacity. The initial sizing is very important. ISVs: HP Data Protector Express or Symantec Backup Exec are typical backup applications in this segment. See http://www.hp.com/go/connect and http://www.hp.com/go/ebs. 60 D2D Systems