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Data is one of the most valuable assets to an organization. Users (and sometimes their customers) access data constantly, directly and indirectly, using various applications. This makes data a crucial part of day-to-day operations. Outages can occur at any time and can be restricted to a single system or an entire data center or location. Whether they are planned outages such as regular maintenance, or unplanned events such as a power outage, it is a top priority to ensure that critical data is always available. A business-continuity plan for critical data can prevent these costly outages. To protect against different outage scenarios, an organization should plan and implement a data-protection strategy that includes a data-replication solution.
To protect against a storage-system outage, you can use asynchronous or synchronous replication to create a copy of data on a remote system. Replication is a software feature that synchronizes data to a remote system within the same site or a different location. Replicating data helps to provide data redundancy and safeguards against storage-system failures at the main production site. Having a remote disaster recovery (DR) site protects against system and site-wide outages. It also provides a remote location that can resume production and minimize downtime due to a disaster. The PowerStore platform offers many data-protection solutions that can meet DR needs in various environments.
Asynchronous replication is primarily used to replicate data over long distances, but you can use it to replicate to systems within the same location also. The asynchronous replication for PowerStore is designed to have minimal impact on host I/O latency. Host writes are acknowledged once they are saved to the local storage resource, and no other writes are required for change tracking. Because write operations are not immediately replicated to a destination resource, all writes are tracked on the source. This data is replicated during the next synchronization. With protection policies, asynchronous replication uses the concept of a recovery point objective (RPO). The RPO is the acceptable amount of data, which is measured in units of time, that may be lost due to an outage. This delta of time also affects the amount of data that must be replicated during the next synchronization. It also reflects the amount of potential data loss in a disaster scenario.
Synchronous replication is similar to asynchronous replication in that it replicates data between arrays. Synchronous replication differentiates itself from asynchronous in that it can offer an RPO of zero - meaning zero data loss during planned or unplanned outages. Synchronous replication achieves this by always keeping the volume data between two arrays in sync. Over longer distances, synchronous replication can be associated with higher volume latency. For this reason, synchronous replication is primarily used to replicate data over shorter distances or in situations where volume latency is not a concern.
A block Metro Volume provides synchronous replication, spanned across two individual PowerStore clusters for a VMware vSphere Metro Storage Cluster configuration as well as Microsoft Windows Server Failover Clustering (WSFC), Hyper-V, and Linux hosts. A Metro Volume provides disaster avoidance and a load-balancing solution, when participating PowerStore clusters are in the same building or in metro distance. Concurrent active/active host I/O is possible on both sides and is replicated to the remote system. Hosts can connect to both PowerStore clusters simultaneously with active paths for more redundancy (Uniform host configuration). The stretched architecture allows workload mobility and cross-site automated load balancing together with fast recovery for optimized data-center utilization and downtime avoidance.
You can configure all PowerStore native replication features using PowerStore Manager, PowerStore CLI, or REST API. PowerStore can also integrate with Dell metro node, VPLEX, and RecoverPoint for Virtual Machines. While metro node and VPLEX provide a metro volume feature across different storage arrays, RecoverPoint for Virtual Machines supports VM replication for PowerStore. You can configure it using the Unisphere Manager for RecoverPoint user interface.