Pure Storage FlashArray Implementation Deep Dive
This is part 2 of our series on OpenStack disaster recovery. Read Part 1: Understanding Cinder Replication and Disaster Recovery Fundamentals
Building Enterprise DR with Pure Storage and OpenStack
While the concepts of synchronous and asynchronous replication are universal, the implementation details matter enormously. Pure Storage FlashArrays bring sophisticated replication capabilities to OpenStack Cinder that go beyond basic data copying, providing enterprise-grade features that can transform your disaster recovery strategy.
Pure Storage’s Replication Technologies
Pure Storage implements replication through several complementary technologies, each optimized for different use cases and requirements.
ActiveCluster: Synchronous Replication Perfected
Pure Storage’s ActiveCluster technology represents the state-of-the-art in synchronous replication. Rather than simple mirroring, ActiveCluster creates “stretched Pods” that present a unified storage namespace across multiple FlashArrays.
Key ActiveCluster capabilities include:
- True active-active storage with transparent failover
- Sub-60-second recovery times for most failure scenarios
- Automatic path optimization and load balancing
- No single points of failure in the storage infrastructure
The technical implementation uses stretched Pods that span arrays, allowing applications to access data from either site transparently. When configured properly, applications may not even detect a site failure—the ActiveCluster technology handles failover automatically at the storage layer.
Protection Groups: Flexible Asynchronous Replication
For asynchronous replication, Pure Storage uses Protection Groups that provide snapshot-based replication with sophisticated retention policies. This isn’t just simple snapshot copying—it’s a comprehensive data protection framework.
Protection Groups offer:
- Configurable replication intervals from minutes to hours
- Multi-tier retention policies (hourly, daily, weekly, monthly)
- Application-consistent snapshots for complex workloads
- Bandwidth optimization through compression and deduplication
Tri-Sync: The Best of Both Worlds
One of Pure Storage’s unique OpenStack capabilities is tri-sync replication, which combines synchronous and asynchronous replication for a single volume. This allows you to maintain zero-RPO protection to a nearby site while simultaneously protecting against regional disasters with asynchronous replication to a distant location.
Tri-sync scenarios work particularly well for:
- Financial institutions requiring both local and regional disaster recovery
- Healthcare systems with compliance requirements for multiple recovery sites
- Critical infrastructure that cannot tolerate any data loss but needs geographic diversity
I wrote a more detailed post on tri-sync replication some time ago. Check it out here.
OpenStack Integration Architecture
Implementing Pure Storage replication with OpenStack Cinder requires careful configuration that balances flexibility with operational simplicity.
Driver Configuration Fundamentals
Pure Storage provides unified drivers for iSCSI, Fibre Channel, and NVMe protocols. The basic configuration requires several key parameters:
[puredriver-1]
volume_backend_name = puredriver-1
volume_driver = cinder.volume.drivers.pure.PureISCSIDriver
san_ip = <PRIMARY_ARRAY_MGMT_IP>
pure_api_token = <PRIMARY_API_TOKEN>
Replication Device Configuration
Adding replication requires defining replication devices that specify the target arrays and replication characteristics:
replication_device = backend_id:pure-dr,san_ip:<DR_ARRAY_IP>,api_token:<DR_API_TOKEN>,type:async
The type parameter accepts sync or async. If two replication_device settings are provided, one for each replication type and with pure_trisync_enabled : true then tri-sync replication is available.
Volume Type Strategy
Creating effective volume types is crucial for operational success. Each volume type should clearly indicate its protection characteristics. For example:
openstack volume type create SyncReplicated
openstack volume type set --property replication_enabled='<is> True' SyncReplicated
openstack volume type set --property replication_type='<in> sync' SyncReplicated
Advanced Configuration Options
Pure Storage’s Cinder integration includes numerous parameters for fine-tuning replication behavior:
Asynchronous Replication Tuning:
pure_replica_interval_default: Controls how frequently snapshots are replicatedpure_replica_retention_short_term_default: Manages short-term snapshot retentionpure_replica_retention_per_day_default: Sets daily snapshot retention policiespure_replication_pg_name: Specifies Protection Group naming for organizational clarity
Synchronous Replication Tuning:
pure_replication_pod_name: Specifies ActiveCluster Pod naming for organizational clarity
Performance Optimization:
pure_automatic_max_oversubscription_ratio: Enables intelligent thin provisioningpure_eradicate_on_delete: Controls whether deleted volumes are immediately destroyed or retained for recovery
Monitoring and Operational Insights
Pure Storage provides extensive metrics through the Cinder and OpenMetrics integration, enabling sophisticated monitoring and alerting:
- Real-time replication status and lag information
- Performance metrics including IOPS, bandwidth, and latency
- Capacity utilization across all replicated volumes
- Array health and connectivity status
These metrics integrate with standard OpenStack monitoring tools and can feed into enterprise monitoring platforms for comprehensive visibility.
Preparing for Production
Before deploying Pure Storage replication in production, consider these preparation steps:
- Network Validation: Ensure adequate bandwidth and latency characteristics for your chosen replication mode
- Security Configuration: Implement proper API token management and network segmentation
- Backup Strategy: Remember that replication complements but doesn’t replace traditional backups
- Testing Framework: Develop procedures for regularly testing failover and recovery processes
In my next post, I’ll explore the innovative Project Aegis, for OpenStack-DR, that revolutionizes how we think about disaster recovery granularity and operational flexibility.
