IBM ProtecTier Implementation and Best Practices Guide

342 IBM ProtecTIER Implementation and Best Practices Guide

Aborting replication tasks

Aborting replication tasks removes them from the list of pending and running tasks. These

tasks automatically re-execute if the specific cartridge is:

򐂰 Appended

򐂰 Ejected from the library

򐂰 Selected for manual execution

To prevent these replication tasks from re-executing, mark those cartridges as

read-only

either on the ProtecTIER server, or by the backup application. These cartridges are not used

for further backups, and therefore do not replicate the backlog. New (scratch) sets of

cartridges are used for subsequent backups, and do not contain backlog data that does not

need to be replicated.

21.4 Many-to-one replication

ProtecTIER many-to-one replication offers the following enhanced features and benefits:

򐂰 Setting replication performance limits: The most significant many-to-one replication

enhanced feature is the capability to set system-wide physical and nominal limits for the

maximum replication transfer rate allowed in the network for a specific repository. The

performance limit reflects the overall resource consumption of the system. The network

transfer rate reflects the performance limits.

򐂰 Enhancements to the replication rate control mechanism: Currently, the replication rate

control (RRC) is used when a user does not provide a time frame and the system

replicates continuously. The

rate calculation determines the maximum rate possible in

both levels of system usage (IDLE and BUSY), and normalizes the rate accordingly.

򐂰 Reserving local-backup-only space for the hub repository: You can use this enhancement

to exclusively assign a portion of a hub repository for local backups. In large deployments

with many spokes replicating, capacity management might cause replication to occupy all

the space in hub repository.

Because a backup has higher priority over replication, this enhancement was added to

ensure that capacity is reserved only for local backup. Replication cannot be written to this

portion of the hub repository. Error notifications display if the repository hub areas

reserved for local backup or replication are reaching maximum capacity.

򐂰 Enhanced monitoring of repository space consumption: A new GUI feature that provides

an at-a-glance view of the proportion of the repository data, replication data, local backup

data, and free space.

21.4.1 Planning for replication

ProtecTIER systems with replication require more planning than systems used only as a local

VTL. When a multiple-site, many-to-one topology is deployed, the entire configuration,

including all spokes and hub environments, are considered.

Tip: To resume I/O activity, use different barcodes. Because the earlier data on the older

cartridges is replicated before the new data, the backlog is too large to manage. Using a

different set of barcodes allows the new data to be replicated, and you can skip replication

of the data from the old cartridges.