5 1 0:Replication Best Practices
Overview
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Replication is the process of copying data from one host to another (between backup-to-disk devices capable of replication) in a block-level, incremental fashion and is an important subset of the larger disaster recovery (DR) effort.
SEP sesam provides different replication types. SEP Si3 replication enables you to replicate data between SEP sesam Server and SEP sesam Remote Device Server (RDS) or between two RDSs. You can also use HPE Catalyst stores and HPE Cloud Bank Storage, or S3 cloud storage as replication targets. For details, see About Replication.
Below are some important best practices to follow to make sure your data is replicated efficiently and effectively.
Establishing a data replication strategy
General considerations
How much disk space is needed on the target server?
Replication needs to consider the current amount of existing data in order to determine the size of the disk space on the source and the target server, which should be at least the same. Since the data is only replicated once, it is more important to consider the volume of new data created on a daily basis since new data will always need to be replicated. Ensure that you have at least the same amount of space available for your source and target media pools.
Can the retention times of the source and target media pool be different?
Different retention times of replication media pools are supported. The target media pool should be the same size or larger than the source media pool. And it should have the same or a longer retention time set. Therefore, the replicated savesets have at least the same or a longer EOL (end-of-life) as the original backup. For details, see Managing EOL.
Determine the available network bandwidth between locations
Data replication can place a huge strain on network bandwidth, especially if large amounts of data are being replicated to multiple servers. The rate of change of your applications will impact the bandwidth requirements of your replication solution and also your RPO (Recovery Point Objective) requirements. Ideally, you should have a dedicated connection between servers. The amount of data to be copied also determines the network bandwidth required to transfer this amount of data.
Test your data replication and disaster recovery plan
Test your DR environment to make sure you have addressed any possible infrastructure changes. Also test the sequence of operations to ensure that all systems are communicating properly and that replicated files are accessed frequently to ensure they have not been corrupted.
Replication checklist
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1. Replication licenses
Depending on your environment (Si3R, HPE StoreOnce VSA, Cloud Storage), a valid replication license is required. For details, see Licensing.
2. Use a high-performance disk
Ensure that there is enough disk space in the media pool on the target – at least as much as on the source server and that your storage can be extended to meet deduplication requirements. Always keep in mind that horizontal scaling may be required.
The disk you use for replication should have at least 1 TB free hard disk space.
3. Processor cores and memory
When replicating to Si3 deduplication store, it is important to ensure a sufficient amount of memory and CPU (cores), as described in Si3 Deduplication Hardware Requirements. You should be familiar with these requirements to ensure smooth replication and operation of Si3 deduplication store.
4. Network connection
Ensure that there is a reliable network connection between the servers.
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5. Rate of data change (churn)
The rate of data change (the volume of new data created each day) is an important consideration, as new data must always be replicated. Also consider the changes users make to existing files.
The rate of change of your data affects the bandwidth requirements of your replication solution and your recovery point objective (RPO) requirements. A high rate of change refers to data that is constantly changing. If you have a low change rate, your RPO can be longer.
6. Bandwidth requirements based on the amount of replicated data
Replication, rate of change and bandwidth are interrelated because the amount of data that needs to go across the bandwidth to the target site varies depending on the rate of change.
Calculate the available network bandwidth between locations as it can affect replication performance. Test the SEP sesam replication processing to determine how much workload can be managed by your network.
7. Determining the replication source and scheduling
Specify the data (so the media pool) to be replicated. You can reduce network load by elaborate scheduling and replication scenarios. To automate your replication, add your replication task to one or more schedules:
- In the Main Selection -> Scheduling -> Schedules, click New Schedule. The New Schedule window is displayed.
- Configure your schedule and click OK.
- Right-click the schedule you have just created and select New Replication Event. The New Replication Event window is displayed.
- From the Task name drop-down list, select the replication task you want to link to the schedule.
- Optionally, check the parameters, then click OK to link the event to the schedule.
For a step-by-step procedure, see Scheduling Replication.
See also
About Replication – Configuring Si3 Replication – S3 Cloud Replication – Configuring HPE StoreOnce Replication – Deduplication