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Infinidat embeds SAN, NAS replication in InfiniBox R4

Infinidat's software upgrade eschews SCSI in favor of custom IP-based replication protocol. The vendor claims InfiniBox R4 delivers target writes at sub-400-millisecond latency.

Infinidat has checked off several roadmap items for its high-end InfiniBox storage system, including "near-zero impact" SAN synchronous replication and the ability to define quality of service for individual applications, tenants and subtenants.

The InfiniBox R4 upgrade also added asynchronous NAS replication and NAS directory quota management to combat file system sprawl. Those features are among more than 150 enhancements to the R4 operating system.

Infinidat claims InfiniBox unified arrays are faster than all-flash, although they store all data on hard disk drives. The modular design includes three controllers in an active-active-active configuration for high availability. InfiniBox is geared to enterprises with petabyte-scale storage, competing with high-end storage arrays from Dell EMC, NetApp, Hitachi Vantara, IBM and Hewlett Packard Enterprise.

InfiniBox serves most I/O traffic from dynamic RAM (DRAM), and includes a small dose of flash as an acceleration tier. Artificial intelligence and machine learning tools orchestrate data tiering. The InfiniFlash system learns over time the best media placement to generate high hit rates out of DRAM.

Adding synchronous replication makes Infinidat a better play with hyper-scale enterprises and managed service providers, IDC storage analyst Eric Burgener said.

"Infinidat targets InfiniBox for dense workload consolidation," Burgener said. "It was somewhat limited in that it only offered asynchronous replication, which does not give a zero [recovery point objective]. This was a gap in the product line that they needed to fill. Their customers are now going to be more comfortable taking most of their mission-critical applications and putting it on this platform."

Infinidat custom IP protocol drives synchronous replication

Rather than SCSI-based replication, Infinidat wrote a custom IP-optimized protocol that requires fewer network hops to acknowledge writes. Replication occurs directly on the remote node that manages the data.

Infinidat also reduced metadata processing by carrying only 180 bytes for each 64K of data. The replication occurs close to the silicon using an approach similar to Remote Direct Memory Access.

Infinidat said its asynchronous replication delivers target write latency in the sub-400-millisecond range on nearby systems, and scales linearly to keep performance consistent as replicas are added.

The system is designed to prevent data loss as volumes are synchronized. Users can configure it to transparently fall back to asynchronous replication to handle failure scenarios for mission-critical applications.

Infinidat took its time to develop its own replication technique, rather than rush to add the feature, the company's CMO Randy Arseneau said.

"This was a very complicated computer science and mathematics problem to solve," Arseneau said. "It would have been easy for us to implement replication as a 'me too' feature using a legacy approach, but that would violate our prime directive. We will not implement features using a traditional bolt-on technique just to get something to market faster. We architect features to embed them in our core OS as a way to mitigate processing and resource consumption."

Infinidat added NAS support in 2015. New asynchronous NAS replication in R4 enables a recovery point objective of 4 seconds. Infinidat uses a CPU-accelerated process called InfiniSnap that supports billions of snapshots per replicated file system. Replication mostly occurs in DRAM to avoid stalling I/O requests.

Infinidat quality of service takes cues from all-flash arrays

Infinidat also added NAS TreeQ as a tool for managing NAS directory quotas. It allows administrators to apply hard quotas across multiple file systems. Resources can be allocated for a specific application or project with reporting in InfiniMetrics.

Most all-flash arrays offer quality of service (QoS), although the feature usually isn't a deal-breaker for most customers. All-flash systems typically have sufficient overhead for bursting workloads. QoS becomes critical as array takes on more workloads.

Infinidat QoS allows resources to be partitioned by tenant or volume within an InfiniBox system. Tenants can allocate resources to multiple nested subtenants for more granular control of storage resources. Having it built into InfiniBox is another must-have capability, Burgener said.

"Infinidat's QoS capability allows them to set the service level at low, medium or high and quantitatively guarantee it can deliver the performance where it's needed. This is an issue for service providers and for on-premises clouds as well," Burgener said.

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