HP StoreOnce Backup System Concepts and Configuration Guidelines (BB877-90913, November 2013)

Figure 63 Backup application tape offload at StoreOnce source site for VTL and NAS device types
1. Copy StoreOnce device to physical tape; this uses the backup Copy job to copy data from the StoreOnce appliance
to physical tape and is easy to automate and schedule, it has a slower copy performance.
2. Mirrored backup; specific backup policy used to back up to StoreOnce and Physical Tape simultaneously (mirrored
write) at certain times (monthly). This is a faster copy to tape method.
As can be seen in the diagrams above – offload to tape at the source site is somewhat easier
because the backup server has written the data to the StoreOnce Backup system at the source site.
In the StoreOnce Target site scenario (Figure 30), some of the data on the StoreOnce Backup
system may have been written by Backup Server B (local DR site backups, maybe) but the majority
of the data will be on the StoreOnce Target via low bandwidth replication from StoreOnce Source.
In this case, the Backup Server B has to “learn” about the contents of the StoreOnce target before
it can copy them and the typical way this is done is via “importing” the replicated data at the
StoreOnce target into the catalog at Backup Server B, so that it knows what is on each replicated
virtual tape or StoreOnce NAS share. Copy to physical tape can then take place. These limitations
do not exist if HP StoreOnce Catalyst device types are used.
HP StoreOnce Optimum Configuration for Tape Offload
Optimizing tape offload from HP StoreOnce Backup System is achieved by reading multiple data
streams simultaneously into a backup application, which combines the data streams into a single
data stream (multiplexing). This single data stream is now fast enough to send to a HP LTO Ultrium
Tape Device and maintain streaming, hence ensuring optimal throughput and minimal offload
time.
To achieve multiple data streams on a HP StoreOnce Backup System, create an offload job in the
backup application, which reads from multiple objects stored on the HP StoreOnce Backup System
simultaneously, then using the backup application’s multiplexing option to write to a single HP LTO
physical tape.
Offload Considerations
VTL Cloning/Media Copy to Physical Tape
This process involves transferring all backup data held on a VTL cartridge directly to a physical
tape making an identical copy of the data. This type of tape offload generally does not support
appending, therefore it is best practice to match the VTL cartridge size to the Physical cartridge
size. (May Not Apply To All Backup Applications)
112 Tape Offload