378 IBM ProtecTIER Implementation and Best Practices Guide
3. Verifies cyclic redundancy check (CRC) for all replicated data before it becomes available
as part of the cartridge.
4. After the CRC check proves successful, the system moves each of the verified data
elements into the cartridge scope and makes it available for the user.
After all the verified data is inserted into the cartridge, it becomes available as a complete
cartridge. However, as a replica in the destination (DR) repository, it is set as read-only and
cannot be used for backup purposes. This factor is important in failover situations when the
DR system might temporarily become the production site and can accept local backups. At
that time, the user must create new tapes to accept the local backed-up data. These new
local DR site tapes can be replicated to the primary site after it becomes available and ready
for production again.
During the failback process, the user moves operations back to the primary site. The newly
created cartridges from the DR site can be replicated to the primary site. Under these
circumstances, the system grants read and write permissions to these replicated cartridges at
the primary site. That site becomes the
owner of these tapes from that point on, just as
though they were created there.
22.2 Replication prerequisites for the source and target sites
For each of the tasks listed, see IBM System Storage TS7650G ProtecTIER Deduplication
Gateway Installation Roadmap Guide, GA32-0921, for Gateway hardware installation
instructions. See IBM System Storage TS7650 ProtecTIER Deduplication Appliance
Installation Roadmap Guide, GA32-0920, for Appliance hardware installation instructions.
22.2.1 Installing the TS7650 Appliance or the TS7650G: Overview
The following procedure provides the general procedure for installation of the TS7650
Appliance or the TS7650G:
1. Install the TS7650 Appliance hardware.
2. Install the IBM TS3000 System Console (TSSC) hardware. The TSSC code level used for
a ProtecTIER Version 3.2 installation
must be Version 5.11.5 or higher. If the TSSC
version is lower than 5.11.5, the TSSC operating system must be reimaged using the
procedure described in Software Upgrade Guide for the TS7650 ProtecTIER
Deduplication Appliance and TS7650G ProtecTIER Deduplication Gateway, SC27-3643.
3. Configure the RAS package on the ProtecTIER servers. The RAS code level used for all
ProtecTIER Version 3.2 installations must be M10518.45E9826.
Tip: A cartridge replica in the destination repository is always read-only and cannot be
used to perform backups; it can be used only for restore purposes. If backup execution is
required while in a DR situation, new scratch cartridges must be created at the remote site.
These cartridges are later replicated back to the primary site during the failover process.
Hint: The replication data-transfer process requires the replicated cartridge to be on the
remote (DR) site ProtecTIER shelf. While the data transfer is being performed, these
cartridges cannot be moved from the shelf. If the cartridge is manually moved from the
shelf, it can cause replication errors if replication is attempted.