How to Purchase a Hybrid SAN or All-Flash SAN Storage Array that Fits Your Environment

Over the last decade, data storage technology has made quantum leaps in performance, reliability, and functionality to keep up with companies' ever-growing data generation and retrieval requirements. These advancements in storage technology have not only come in the form of raw hardware, but primarily in the form of intelligent data management software and innovative approaches to hardware architecture. While higher performance storage systems are becoming increasingly adopted by companies worldwide, there are still numerous applications for legacy storage arrays - making it potentially difficult to discern the best fit for your unique environment. Here we will discuss the three main storage array types: Spinning Disk, Hybrid, and All-flash, as well as tips for choosing the most suitable storage solution for your IT infrastructure.

Spinning Disk Arrays

Of the three types of storage arrays, spinning disk arrays have the longest history and, while flash-based systems are becoming more prevalent, most small to medium-sized companies still utilize spinning disk arrays for in their production data environment. These arrays are comprised solely of spinning hard disk drives (HDDs), typically with SATA, NL-SAS, or SAS interfaces. Unlike Solid State Drives (SSDs), HDDs can vary greatly in their performance capabilities - with the most common variants being 7.2k RPM, 10k RPM, and 15k RPM. Many storage vendors have developed automated data tiering algorithms that allow users to combine HDDs with different performance levels. Auto-tiering software then recognizes the different performance levels and effectively migrates users' frequently accessed data to the highest performance drives in the storage pool to deliver higher performance on users" most commonly accessed and critical data. This software functionality, combined with the unmatched price per GB of HDDs, makes spinning disk arrays ideal for bulk backup data repositories, secondary DR sites, and environments with low to moderate IO demands (typically < 5,000 IOPS). While spinning disk arrays can provide extreme performance, they require hundreds of HDDs to match the performance of SSDs - resulting in far more capacity than most users require. Hybrid Arrays solve this problem by combining SSDs and HDDs within a single array.

Hybrid Arrays

Hybrid Arrays include both SSDs and HDDs within the same device. This allows users to realize the high capacity benefits of HDDs while also realizing the extreme performance advantages of SSDs. To keep costs low while maximizing capacity, the SSDs within the system usually comprise a small portion (typically 10%) of the total usable space on the array, where the SSDs are employed to deliver extreme performance to users' most critical data. This makes Hybrid Arrays an ideal storage solution for companies with moderate to high IO requirements (5,000 IOPS - 30,000 IOPS), or companies with only a relatively small amount of data that requires high performance, such as an IO-intensive SQL database or CAD application, which can be dedicated to the SSD layer to guarantee flash performance. Most hybrid storage vendors leverage the SSDs as either an SSD Cache layer or an SSD Tier layer. When leveraged as a cache layer, the SSDs are used to handle all new writes and reads to the array, but do not intelligently make sense of the data. When leveraged as a tier layer, the SSDs are used alongside autotiering software to handle users' most frequently accessed data, but this architecture does not necessarily deliver flash performance to all new reads and writes to the system. Since each implementation approach has an inherent flaw, StorTrends employs the SSDs in the 3500i SSD Hybrid SAN as both a cache and tier layer to mitigate each architecture's flaws and deliver sustained flash performance across the system. However, even with numerous innovative approaches to hybrid storage architecture, they still pale in comparison to the performance and reliability of all flash arrays (AFAs).

All Flash Arrays

All Flash Arrays are comprised of solely SSDs and offer users the highest levels of both performance and reliability than any other commercially available storage system. In the past, AFAs have been reserved exclusively for large companies and enterprises due to their high price tag. However, as the price of SSDs continues to drop and storage vendors have refined breakthrough technologies such as deduplication and compression, all flash arrays are becoming increasingly viable options for small to medium sized organizations as well. Due to the inherent performance capabilities of SSDs, All Flash Arrays are ideal storage solutions for companies with extreme IO requirements (30,000 - 250,000 IOPS), or simply for companies who want guaranteed flash performance for 100% of their data and the assurance that they are investing in the most advanced storage technology available. Also, whereas HDDs are mechanical in nature and therefore susceptible to random failure, SSDs have no moving parts - making All Flash Arrays ideal solutions for IT infrastructures with little to no tolerance for downtime.


While storage systems have radically evolved over a relatively short time period, there are still instances in which spinning disk and hybrid arrays are suitable solutions for users' IT requirements. However, it is often difficult to identify a company's storage requirements, such as capacity, performance needs, and data growth - making it difficult to discern the most suitable storage solution for your unique environment.

StorTrends iDATA Tool

StorTrends has developed a performance analysis tool called the StorTrends iDATA tool to help IT professionals make the best storage decisions for them and their company. The StorTrends iDATA tool runs non-intrusively in users' environments for 7 days, then generates a report including total storage capacity, forecasted growth, IOPS, latency, CPU usage, and more. The tool can be downloaded free of charge from the StorTrends website here.