Source:Replication Best Practices

From SEPsesam

Copyright © SEP AG 1999-2024. All rights reserved.

Any form of reproduction of the contents or parts of this manual is allowed only with the express written permission from SEP AG. When compiling and designing user documentation SEP AG uses great diligence and attempts to deliver accurate and correct information. However, SEP AG cannot issue a guarantee for the contents of this manual.

Docs latest icon.png Welcome to the latest SEP sesam documentation version 4.4.3/4.4.3 Grolar. For previous documentation version(s), check Documentation archive.


Overview

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 a fast, flexible and reliable data replication solution for disaster protection. SEP Si3 replication is a solution that consistently replicates data between a SEP sesam Server and a SEP sesam Remote Device Server (RDS), or between two Remote Device Servers.

Below are some important best practices to keep in mind to make sure your data is restored 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 data will only be replicated once, it is more important to consider the volume of new data created on a daily basis since new data will always have to be replicated. Ensure that you have at least the same amount of space available for your source and target media pool.

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 should be larger than the source media pool. And it should have the same or a longer retention time set. Therefore the replicated save sets have at least the same or a longer EOL (end-of-life) as the original backup.

Determine available network bandwidth between locations

Data replication can place a huge strain on a network's 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 impact your RPO (Recovery Point Objective) requirements. Ideally, you should have a dedicated connection between servers. The amount of data that needs to be copied will also determine the bandwidth of the network required to move that 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. In addition, the order of operations must also be tested to be certain that all systems communicate properly and replicated files need to be accessed frequently to make sure they have not become corrupted.

Replication checklist

Information sign.png Note
  • Ensure that the SEP sesam Server and Remote Device Servers have the same SEP sesam version installed. You can have more than one RDS, but their SEP sesam version must match the SEP sesam Server version.
  • You will require a valid replication license Si3R for each Si3T node (SEP sesam Server or Remote Device Server).
  • Because SEP sesam replicates data between a SEP sesam Server and an RDS (or between two RDSs), make sure that, in addition to the SEP sesam server, either two RDSs or one RDS are configured for the replication. See How to create a Remote Device Server (RDS).

1. Use a high-performance disk

Ensure that enough disk space is available in the media pool on the target server (at least as much as on the source server) and that your storage can be extended for the needs of deduplication. Always keep in mind that horizontal scaling might be necessary.

The disk you use for replication should have:

  • a minimum of 1 TB free hard disk space
  • a minimum capability of xxx I/O operations per second (IOPS)

2. Processor cores and memory

It is important that you ensure sufficient amount of memory and CPU (cores). The minimum processor core and memory requirements as as follows:

For TEST environments:

  • 8 GB RAM
  • 2 CPU cores

For PRODUCTIVE environments:

  • 16 GB RAM
  • 4 CPU cores for one Si3 data store

For details, see Configuring and Administering Si3 Deduplication Store by using CLI for information on the amount of additional RAM required for one Si3 data store.

3. Network connection

Ensure that there is a reliable network connection between servers.

Information sign.png Note

NAT (Network Address Translation) infrastructure is not supported.

4. Rate of data change (churn)

The rate of data change (the volume of new data created each day) is an important consideration since new data will always have to be replicated. Take into account also the changes that users make to existing files.

The rate of change of your data will impact 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 rate of change, your RPO can be longer.

5. Bandwidth requirements based on the amount of replicated data

Replication, rate of change and bandwidth are related because the amount of data that needs to go across the bandwidth to the target site varies based on rate of change.

Calculate available network bandwidth between locations as it can affect replication performance. Test SEP sesam replication processing to determine how much workload can be managed by your network.

6. Type of data

Determine the type of data that is going 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:

  1. In the Main Selection -> Scheduling -> Schedules, click New schedule. The New schedule window appears.
  2. Configure your schedule and click OK.
  3. Right-click the schedule you have just created and select New migration event. A new tab is opened in the schedule window.
  4. From the Task name drop-down list, select the task you want to link to the schedule.
  5. Check the parameters and set filters, if needed, then click OK to link the event to the schedule.

For more details on creating a schedule, see Creating a Schedule.

See also

SEP Si3 replicationHow to create a Remote Device Server (RDS)Configuring Si3 Deduplication Store