PowerFlex Native Asynchronous Replication RPO with Oracle
Mon, 17 Aug 2020 15:52:45 -0000
|Read Time: 0 minutes
PowerFlex software-defined storage platform provides a reliable, high-performance foundation for mission-critical applications like Oracle databases. In many of these deployments, replication and disaster recovery have become a common practice for protecting critical data and ensuring application uptime. In this blog, I will be discussing strategies for replicating mission-critical Oracle databases using Dell EMC PowerFlex software-defined storage.
The Role of Replication and Disaster Recovery in Enterprise Applications
Customers require Disaster Recovery and Replication capabilities to meet mission-critical business requirements where SLAs require the highest uptime. Customers also want the ability to quickly recover from physical or logical disasters to ensure business continuity in the event of disaster and be able to bring up the applications in minimal time without impact to data. Replication means that the same data is available at multiple locations. For Oracle database environments, it is important to have local and remote replicas of application data which are suitable for testing, development, reporting, and disaster recovery and many other operations. Replication improves the performance and protects the availability of Oracle database application because the data exists in another location. Advantages of having multiple copies of data being present across geographies is that, critical business applications will continue to function if the local Oracle database server experiences a failure.
Replication enables customers in various scenarios such as:
- Disaster Recovery for applications ensuring business continuity
- Distributing with one type of use case such as analytics
- Offloading for mission-critical workloads such as BI, Analytics, Data Warehousing, ERP, MRP, and so on
- Data Migration
- Disaster Recovery testing
PowerFlex Software-Defined Storage – Flexibility Unleashed
PowerFlex is a software-defined storage platform designed to significantly reduce operational and infrastructure complexity, empowering organizations to move faster by delivering flexibility, elasticity, and simplicity with predictable performance and resiliency at scale. The PowerFlex family provides a foundation that combines compute as well as high performance storage resources in a managed unified fabric.
PowerFlex is designed to provide extreme performance and massive scalability up to 1000s of nodes. It can be deployed as a disaggregated storage / compute (two-layer), HCI (single-layer), or a mixed architecture. PowerFlex inclusively supports applications ranging from bare-metal workloads and virtualized machines to cloud-native containerized apps. It is widely used for large-scale mission-critical applications like Oracle database. For information about best practices for deploying Oracle RAC on PowerFlex, see Oracle RAC on PowerFlex rack.
PowerFlex also offers several enterprise-class native capabilities to protect critical data at various levels:
- Storage Disk layer: PowerFlex storage distributed data layout scheme is designed to maximize protection and optimize performance. A single volume is divided into chunks. These chunks will be striped on physical disks throughout the cluster, in a balanced and random manner. Each chunk has a total of two copies for redundancy.
- Fault Sets: By implementing Fault sets, we can ensure the persistent data availability at all time. PowerFlex (previously VxFlex OS) will mirror data for a Fault Set on SDSs that are outside the Fault Set. Thus, availability is assured even if all the servers within one Fault Set fail simultaneously. Fault Sets are subgroup of SDSs installed on host servers within a Protection Domain.
PowerFlex replication overview
PowerFlex software consists of a few important components - Meta Data Manager (MDM), Storage Data Server (SDS), Storage Data Client (SDC) and Storage Data Replicator (SDR). MDM manages the PowerFlex system as a whole, which includes metadata, devices mapping, volumes, snapshots, system capacity, errors and failures, system rebuild and rebalance tasks. SDS is the software component that enables a node to contribute its local storage to the aggregated PowerFlex pool. SDC is a lightweight device driver that exposes PowerFlex volumes as block devices to the applications and hosts. SDR handles the replication activities. PowerFlex has a unique feature called Protection Domain. A Protection Domain is a logical entity that contains a group of SDSs. Each SDS belongs to only one Protection Domain.
Figure 1. PowerFlex asynchronous replication between two systems
Replication occurs between two PowerFlex systems designated as peer systems. These peer systems are connected using LAN or WAN and are physically separated for protection purposes. Replication is defined in scope of a protection domain. All objects which participate in replication are contained in the protection domain, including volumes in Replication Consistency Group (RCG). Journal capacity from storage pools in the protection domain is shared among RCGs in the protection domain.
The SDR handles replication activities and manages I/O of replicated logical volumes. The SDR is deployed on the same server as SDS. Only I/Os from replicated volumes flows through SDR.
Replication Data Flow
Figure 2. PowerFlex replication I/O flow between two systems
- At the source, application I/O are passed from SDS to SDR.
- Application I/O are stored in the source journal space before it is sent to target. SDR packages I/O in bundles and sends them to the target journal space.
- Once the I/O are sent to target journal and get placed in target journal space, they are cleared from source.
- Once I/O are applied to target volumes, they are cleared from destination journal.
- For replicated volumes, SDS communicates to other SDS via SDR. For non-replicated volumes, SDS communicates directly with other SDS.
For detailed information about Architecture Overview, see Dell EMC PowerFlex: Introduction to Replication White Paper.
It is important to note that this approach to replication allows PowerFlex to support replication at extreme scales. As the number of nodes contributing storage are scaled, so are the SDR instances. As a result, this replication mechanism can scale effortlessly from 4 to 1000s of nodes while delivering RPOs as low as 30 seconds and meeting IO and throughput requirements.
Oracle Databases on PowerFlex
The following illustration demonstrates that the volumes participating in replication are grouped to form the Replication Consistency Group (RCG). RCG acts as the logical container for the volumes.
Figure 3. PowerFlex replication with Oracle database
Depending on the scenario, we can create multiple RCGs for each volume pair or combine multiple volume pairs in a single RCG.
In the above Oracle setup, PowerFlex System-1 is the source and PowerFlex System-2 is the destination. For replication to occur between the source and target, the following criteria must be met:
- A volume pair must be created in both source and target.
- Size of volumes in both source and target should be same. However, the volumes can be in different storage pools.
- Volumes are in read-write access mode on the source and read-only access mode in secondary. This is done to maintain data integrity and consistency between two peer systems.
The PowerFlex replication is designed to recover from as low as a 30 seconds RPOs minimizing the data-loss if there is a disaster recovery. During creation of RCG, users can specify RPO starting from 30 seconds to maximum of 60 minutes.
All the operations performed on source will be replicated to destination within the RPO. To ensure RPO compliance, PowerFlex replicates at least twice for every RPO period. For example, setting RPO to 30 seconds means that PowerFlex can immediately return to operation at the target system with only 30 seconds of potential data loss.
The following figures depicts the replication scenario under steady state of workload:
Figure 4. 100% RPO compliance for RPO of 30s for an Oracle database during a steady application workload
Figure 5. Replication dashboard view of PowerFlex
Disaster Recovery
In the case of disaster recovery, the entire application can be up and running by failover to secondary, with less than 30 seconds of data loss.
When we do a planned switchover or failover, the volumes on secondary system are automatically changed to read-write access mode and the volumes on source will be changed to read-only. Consequently, we can bring up Oracle database on secondary by setting up the Oracle environment variables and starting the database.
Once we have RCG in the failover or switchover mode, user can decide how to continue with replication:
- Restore replication: Maintains the replication direction from original source to destination.
- Reverse replication: Changes the direction so that original destination becomes the source and replication will begin from original destination to original source.
PowerFlex also provides various other options:
- Pause and Resume RCG: If there are network issues or user need to perform maintenance of any of the hardware. While paused, any application I/O will be stored at source journal and is replicated to the destination only after the replication is resumed.
- Freeze and Unfreeze RCG: If the user requires consistent snapshot of the source or target volumes. While frozen, replication will still occur between source journal and destination journal, nonetheless the target journal holds on to the data and do not apply them to the target volumes.
PowerFlex native volume replication is a unique solution and provides customers with easy to configure and setup without worrying about disaster.
Irrespective of workload and application, it is designed to support massive scale while providing RPOs as low as 30 seconds.
For more information, please visit: DellTechnologies.com/PowerFlex.
Related Blog Posts
Deploying Tanzu Application Services on Dell EMC PowerFlex
Tue, 15 Dec 2020 14:35:58 -0000
|Read Time: 0 minutes
Introduction
Tanzu Application Service (TAS) architecture provides the best approach available today to enable agility at scale with the reliability that is must to address these challenges. PowerFlex family offers key value propositions of traditional and cloud-native production workloads, deployment flexibility, linear scalability, predictable high performance, and enterprise-grade resilience.
Tanzu Application Service (TAS)
The VMware Tanzu Application Service (TAS) is based on Cloud Foundry –an open-source cloud application platform that provides a choice of clouds, developer frameworks, and application services. Cloud Foundry is a multi-cloud platform for the deployment, management, and continuous delivery of applications, containers, and functions. TAS abstracts away the process of setting up and managing an application runtime environment so that developers can focus solely on their applications and associated data. Running a single command—cf push—creates a scalable environment for your application in seconds, which might otherwise take hours to spin up manually. TAS allows developers to deploy and deliver software quickly, without the need of managing the underlying infrastructure.
PowerFlex
PowerFlex (previously VxFlex OS) is the software foundation of PowerFlex software-defined storage. It is a unified compute, storage and networking solution delivering scale-out block storage service designed to deliver flexibility, elasticity, and simplicity with predictable high performance and resiliency at scale.
The PowerFlex platform is available in multiple consumption options to help customers meet their project and data center requirements. PowerFlex appliance and PowerFlex rack provide customers comprehensive IT Operations Management (ITOM) and life cycle management (LCM) of the entire infrastructure stack in addition to sophisticated high-performance, scalable, resilient storage services. PowerFlex appliance and PowerFlex rack are the two preferred and proactively marketed consumption options. PowerFlex is also available on VxFlex Ready Nodes for those customers interested in software-defined compliant hardware without the ITOM and LCM capabilities.
PowerFlex software-define storage with unified compute and networking offers flexibility of deployment architecture to help best meet the specific deployment and architectural requirements. PowerFlex can be deployed in a two-layer for asymmetrical scaling of compute and storage for “right-sizing capacities, single-layer (HCI), or in mixed architecture.
Deploying TAS on PowerFlex
For this example, a PowerFlex production cluster is set up using a Hyperconverged configuration. The production cluster has connectivity to the customer-data network and the private backend PowerFlex storage network. The PowerFlex production cluster consists of a minimum of four servers that host the workload and PowerFlex storage VMs. All the nodes are part of a single ESXi Cluster and part of the same PowerFlex Cluster. Each node contributes all their internal disk resources to PowerFlex cluster.
The PowerFlex management software manages the capacity of all of the disks and acts as a back-end for data access by presenting storage volumes to be consumed by the applications running on the nodes. PowerFlex Manager also provides the essential operational controls and lifecycle management tools. The production cluster hosts the compute nodes that are used for deployment of TAS VMs. TAS components are deployed across three dedicated compute clusters that are designated as three availability zones. These compute clusters are managed by the same 'compute workload' vCenter as the dedicated Edge cluster. The following figure depicts the layout in the lab environment:
Figure 1. PowerFlex production cluster
The compute infrastructure illustrates the best practice architecture using 3 AZ’s using PowerFlex rack in hyperconverged configured nodes. This design ensures the high availability of nodes (i.e., nodes in AZ1 will still function if AZ2 or AZ3 goes down). A dedicated compute cluster in each AZ’s combines to form Isolation Zone (IZ). These AZ’s can be used to deploy and run the TAS stateful workloads requiring persistent storage. On the PowerFlex storage we have created volumes in the backend which are being mapped to vSphere as Datastores.
PowerFlex storage distributed data layout scheme is designed to maximize protection and optimize performance. A single volume is divided into chunks. These chunks will be distributed (striped) on physical disks throughout the cluster, in a balanced and random manner. Each chunk has a total of two copies for redundancy.
PowerFlex can be feature configured optionally to achieve additional data redundancy by enabling the feature Fault sets. Persistent Storage for each AZ could be its own PowerFlex cluster. By implementing PowerFlex feature Fault sets we can ensure that the persistent data availability all time. Fault Sets are subgroup of SDS s (Software defined Storage) installed on host servers within a Protection Domain. PowerFlex OS will mirror data for a Fault Set on SDSs that are outside the Fault Set. Thus, availability is assured even if all the servers within one Fault Set fail simultaneously.
PowerFlex enables flexible scale out capabilities for your data center also provides unparalleled elasticity and scalability. Start with a small environment for your proof of concept or a new application and add nodes as needed when requirements evolve.
The solution mentioned in this blog provides recommendations for deploying a highly available and production-ready Tanzu Application Service on Dell EMC PowerFlex rack infrastructure platform to meet the performance, scalability, resiliency, and availability requirements and describes its hardware and software components. For complete information, see Tanzu Application Services on PowerFlex rack - Solution Guide.
References
Introducing the PowerFlex Management Pack for vRealize Operations
Mon, 02 Nov 2020 13:09:42 -0000
|Read Time: 0 minutes
By Vineeth A C
Achieving operation efficiency in today’s modern cloud infrastructure brings automation to the forefront. Centralized visibility provides a key piece of the insight needed to understand if there are operational inefficiencies for taking actions that mitigate business disruption.
We are pleased to share the general availability of Dell EMC PowerFlex Management Pack for vRealize Operations 8.x. The PowerFlex MP for vROps extends the visibility of PowerFlex systems into vROps where IT can monitor their complete data center and cloud operations. It is available to all PowerFlex rack and appliance customers at no additional cost. This brings additional value to the comprehensive IT operations management functionality delivered by PowerFlex Manager that enables full life cycle management of the unified compute and software defined storage solution.
The management pack queries and collects key PowerFlex metrics for storage, compute, networking, and server hardware using APIs and ingests into vROps that can be visualized using the out-of-the-box dashboards. It also provides a detailed system level view that shows the health status and relationship between different components of the PowerFlex system.
Key features and capabilities
Dashboards: The management pack includes 13 default dashboards showing details of PowerFlex storage, PowerFlex Manager, PowerFlex nodes, network switches, ESXi hosts, and clusters. These configurable dashboards provide user customizable data displays that adjust to meet a wide variety of requirements.
Predefined symptoms and alert definitions: The management pack includes 166 symptom definitions and 152 alert definitions based on engineering best practices for the PowerFlex systems. Symptoms and alerts can be customized by the user to meet the demand of their environment.
Historical data: This is available for all PowerFlex Adapter resource kinds. This data provides a view of consumption over time and includes capacity forecasting based on usage for PowerFlex storage.
Network topology and relationship: The topology tree functionality available in vROps is extremely useful when mapping relationships between nodes, network interfaces, switch port, VLAN, port-channel, and vPC.
Detailed metric collection: In addition to the default dashboards, users have the option of drilling into specific metrics for nearly all available data from the components of PowerFlex system, even if it is not included in a dashboard.
Multiple PowerFlex systems awareness: Ability to group and differentiate multiple PowerFlex systems.
PowerFlex node type differentiation: Ability to identify and classify compute, storage, hyperconverged, and management controller nodes.
Sample dashboards
PowerFlex Details: This dashboard shows all the PowerFlex storage KPIs with historical data providing a view of storage performance utilization over time.
PowerFlex Node Summary: You can monitor the health status of all your PowerFlex nodes and its hardware components in this dashboard.
PowerFlex Networking Performance: This dashboard shows network KPIs like throughput, errors, packet discards with historical data providing a view of network utilization over time.
For customers who have already invested in vRealize Operations, this management pack is a great value add to monitor their PowerFlex systems. It is an end-to-end monitoring and alerting solution for PowerFlex infrastructure using vROps. It helps customers significantly in terms of capacity planning based on the historical data of resource consumption over time. It also helps to identify usage trends and provides insight to understand if there are operational issues/ inefficiencies for taking necessary actions to avoid service outages and mitigate business disruption. This integration with VMware vRealize Operations reduces operational complexity by using a unified platform to monitor and manage private data center infrastructure, as well as hybrid and multi-cloud environments.
References
- Download the PowerFlex Management Pack from the Flexera portal.
- Visit Infohub for product documentation.
- Visit PowerFlex site for complete information about PowerFlex software-defined storage.