Evolution of enterprise storage: NVMe technologies and advantages of All-Flash systems

Enterprise storage systems have undergone a radical transformation over the past decade - from bulky cabinets with mechanical disks to compact and ultra-fast all-flash arrays.

All-flash storage arrays are storage systems built entirely on solid state drives (SSDs), without a single mechanical disk (HDD). This architecture delivers unprecedented performance and reliability, fundamentally changing IT infrastructure capabilities.

Traditional mechanical HDD-based storage systems have long been the standard in the enterprise sector. Their main advantage - low storage costs - has been gradually offset by increasing demands on data processing speed. Information access time measured in milliseconds has become a critical limitation for modern applications.

The advent of NVMe (Non-Volatile Memory Express) revolutionized the storage industry. This interface, specifically designed for solid state drives, has eliminated the bottlenecks of traditional SATA and SAS protocols. NVMe supports parallel processing of up to 64 thousand commands in 64 thousand queues, which exceeds the capabilities of previous technologies by orders of magnitude and corresponds to the capabilities of modern multi-core processors.

Leading storage vendors have integrated NVMe into their solutions in a variety of ways:

• NetApp is developing the ONTAP platform with NVMe over Fibre Channel support;
• Dell EMC created the PowerStore lineup with NVMe over TCP;
• Pure Storage introduced DirectFlash technology for direct access to flash storage;
• HPE optimized Primera and Nimble systems for NVMe storage.

The trend away from specialized storage networks toward standard IP protocols is becoming more and more apparent. NVMe over TCP allows NVMe commands to be sent over a standard TCP/IP network, providing performance comparable to Fibre Channel, but with a much lower total cost of ownership and without the need for a separate infrastructure.

Another major factor in the evolution has been the emergence of capacitive QLC SSDs that offer an attractive price-to-volume ratio. These drives make all-flash solutions economically viable even for applications that have traditionally relied on mechanical SAS 10K RPM disks. As a result, modern storage systems can eliminate HDDs altogether, eliminating the complex caching or data tyering mechanisms common to hybrid systems.

In this context of technological development, today's All-Flash systems represent a new generation of storage systems optimized for a wide range of enterprise applications, from demanding database and virtualization systems to data-intensive artificial intelligence and machine learning (AI/ML) applications.

Storage technologies and applications

Today's enterprise-class storage systems utilize various types of solid state drives, each with its own characteristics and optimized for specific applications. The ITPOD Storage Full Flash lineup utilizes both TLC and QLC technologies, with the choice between the two determined by application requirements and workload characteristics.

Comparing TLC and QLC

SSD drives are based on flash memory cells capable of storing a certain number of bits of information. It is the number of bits in a cell that determines the difference between SSD types:

TLC (Triple Level Cell) drives store 3 bits of information in each memory cell. This strikes a balance between performance, write life and cost. TLC drives provide high speeds for both sequential and random I/O operations while maintaining a significant rewrite life - typically 1000 to 3000 cycles per cell.

A physical feature of TLC is its ability to reliably discriminate between 8 possible charge levels in a cell (2³ = 8 combinations), which requires fairly precise control circuitry but maintains good access speeds. TLC provides stable performance even under the intense mixed loads typical of transactional systems.

QLC (Quad Level Cell) drives store 4 bits in each cell, allowing for higher storage density and lower cost per gigabyte. Physically, a QLC cell must distinguish between 16 charge states (2⁴ = 16 combinations), which complicates the electronics and reduces the speed of operations, especially writes.

QLC drives have a lower rewrite life, typically 300-1000 cycles per cell. However, they offer impressive capacity - today's QLC SSDs can reach up to 61.4TB in a standard form factor, making them an ideal replacement for traditional HDDs.

The main differences between the technologies can be summarized as follows:

Optimal usage scenarios for different types of SSDs

The choice of drive type is directly related to workload and application storage requirements.

TLC NVMe SSDs are optimal for:

• Transactional databases (Oracle, Microsoft SQL Server, PostgreSQL) where low latency and high random I/O performance are critical. The stable response time of TLC drives ensures predictable performance even during peak load hours.
• Critical business applications (SAP, 1C, Oracle EBS) requiring low latency data access and high storage reliability. The longer TLC rewrite life provides an additional margin of safety.
• Virtualization systems with high density virtual machines that generate intensive random I/O. TLC drives provide excellent performance in multi-user environments with heterogeneous workloads.
• Highly loaded OLTP (OnLine Transaction Processing) systems dominated by write operations. High TLC write performance is critical for such systems.

QLC NVMe SSDs perform best in the following scenarios:

• Analytical data storage (Data Warehouse, OLAP) with a preponderance of read operations. QLC provides high sequential read speeds while minimizing storage cost.
• Backup and archival storage systems where data is written infrequently but requires fast recovery. The limited rewrite resource of QLC is not a critical limitation in this case.
• Video surveillance and streaming content systems characterized by intensive sequential writes and occasional reads. QLC provides the required capacity at a moderate cost.
• Big data platforms (Hadoop, Spark), where the key parameter is the cost/TB ratio while maintaining performance that far exceeds the capabilities of HDD.

QLC as a modern replacement for SAS HDD

One of the most promising use cases for QLC SSDs is as a direct replacement for mechanical disks in storage systems. Comparing capacitive QLC drives with modern SAS HDDs shows the impressive advantages of SSD solutions:

• Performance: QLC SSDs deliver up to 100,000 IOPS in random access, whereas SAS HDDs are limited to around 200-300 IOPS. A difference of 300-500 times radically changes the capabilities of the storage system.
• Latency: Data access times on QLC SSDs are 20-100 microseconds, while HDDs require 5-10 milliseconds - a difference of two orders of magnitude.
• Storage Density: A modern 30.7TB QLC SSD replaces up to 20 1.8TB mechanical disks while taking up 10 times less physical space.
• Power consumption: Replacing an HDD enclosure with multiple racks of QLC SSDs can reduce power consumption and heat dissipation by 85-90%.
• Reliability: The lack of mechanical components in SSDs significantly increases their resilience to physical impacts and increases MTBF (Mean Time Between Failure) by 2-3x compared to HDDs.

These benefits make QLC SSDs a cost-effective replacement for mechanical disks, even in systems that have traditionally used HDDs due to the low cost of storage. When all factors are taken into account, including reduced power, cooling and colocation costs, the total cost of ownership of capacitive QLC systems is comparable or even lower than HDD-based solutions.

All-Flash efficiency and future prospects

Total Cost of Ownership (TCO) Analysis

The traditional approach to storage costing, which focuses solely on price per terabyte, does not capture the full picture of lifecycle costs. A comprehensive TCO analysis includes several components:

Capital expenditure (CAPEX):

• Storage system and drive costs;
• Network infrastructure costs;
• Equipment colocation costs (racks, cabling, etc.).

Operating costs (OPEX):

• Power consumption of storage and related systems;
• Cooling and air conditioning;
• Maintenance and Support;
• Administration and management;
• Monitoring and security costs.

Hidden Costs:

• Impact of storage performance on business process efficiency;
• Cost of downtime and performance degradation;
• Non-standard situations (disaster recovery, data migration);
• Trade-offs in application architecture due to storage limitations.

When comparing traditional HDD-based storage with all-flash storage, the following economic effects are observed:

Reduced initial investment: While the cost of all-flash storage in terms of raw capacity may be higher, the real economics look quite different when effective capacity is taken into account. Storage efficiency technologies (deduplication, compression, thin provisioning) can achieve data reduction ratios as high as 3:1, effectively tripling the usable capacity of the system. As a result, the cost per effective terabyte in today's all-flash systems is often lower than traditional HDD arrays.

Reduced colocation costs: Practical implementations show that replacing a standard HDD cabinet (42U) can be realized with only 6U of space when using all-flash with capacitive QLC drives. This reduces rack rental costs in commercial data centers and increases the efficiency of in-house space utilization.

Radically reduced power consumption: The energy efficiency of all-flash systems outperforms HDD solutions by a factor of 8-10. For large installations, this can mean savings of tens and hundreds of thousands of kilowatt hours annually. Even more significant savings are achieved on cooling systems, which traditionally consume energy comparable to the equipment itself.

Storage Technology Trends

Storage technologies continue to evolve rapidly, and a number of trends will shape the evolution of ITPOD Storage Full Flash class systems in the coming years:

Advances in flash memory technology:

• The emergence of PLC (Penta-Level Cell) drives with 5 bits per cell, which will further increase capacity and reduce storage costs;
• New methods of spatial cell placement (3D NAND);
• Increased write density due to new process technologies.

Evolution of access protocols:

• Further evolution of NVMe/TCP with the ability to provide lower latency;
• New versions of the NVMe protocol with support for additional features for enterprise environments;
• Optimization for specific use cases (AI/ML, blockchain, databases).

Integration with compute resources:

• Development of App-on-Controller technology - capabilities to run isolated applications directly on storage controllers;
• Computational Storage - processing data directly on storage media without networking;
• Specialized architectures for Edge Computing.

Automation and Artificial Intelligence (AI):

• Self-optimizing storage systems with machine learning algorithms;
• Predictive analytics for failure prediction and proactive optimization;
• Automated resource allocation based on business priorities.

ITPOD actively monitors these trends and integrates promising technologies into its products. ITPOD Storage Full Flash's modular architecture allows for incremental system upgrades without full hardware replacement, which protects customers' investments and allows them to stay on the cutting edge of technological development.

Conclusion

The move from traditional HDD systems to All-Flash storage represents a transformation in the approach to data storage and processing. With significantly higher performance, lower power consumption and improved storage density, All-Flash solutions are becoming economically viable for an increasingly wide range of applications.

Choosing the right type of storage and system configuration can strike the right balance between performance, reliability and total cost of ownership, which is a key factor in modernizing the IT infrastructure of the modernenterprise.