Having written about Storage Area Networks (SAN) and storage arrays for twenty years, it is interesting to cover the topic again after a hiatus of a few years.
SAN arrays used to be a hot topic with analyst firms like Gartner and IDC issuing regular vendor comparisons and market reports. Those reports have largely disappeared. (The best Gartner can do is publish a Primary Storage Array Magic Quadrant that hardly mentions the word “SAN”). It’s an indicator of the success of software and storage virtualization that the SAN arrays themselves no longer receive the attention they once did.
Another factor is consolidation. Back in the day, there were dozens of firms offering SANs of one kind or another. But many have either fallen by the wayside or been gobbled up by larger players. Dell, for instance, is in the guide a couple of times courtesy of products it developed internally and those it acquired over the years from the likes of EMC and others.
That said, the SAN array remains an integral part of the storage landscape and many thousands of them operate around the country. The basic concept of a SAN remains the same as ever: to connect a number of servers to storage devices to provide data rapidly and afford it adequate protection.
SAN Technology Evolution
The SAN is far from being some holdout from the old days of storage, retained by some companies out of loyalty, familiarity, or stubborn determination to eke out every last dollar they spent on it five or more years ago. The technology has evolved markedly.
The world of the SAN has gotten faster with iSCSI and Fibre Channel (FC), and has evolved to include virtualization with vSAN technology. We’ve also seen the emergence of intelligent fabrics and greater cost effectiveness courtesy of iSCSI (running SCSI over traditional IP networks rather than having to invest in a more expensive FB fabric).
Thus there are two SAN choices – FC and IP. Virtualization has also come a long way in hiding the details of where data is stored under an abstraction layer. This enables storage administrators to let the system keep track of physical storage and split-path architectures supported by SANs.
Ten years ago, the SAN was a somewhat esoteric part of the storage landscape. SAN arrays and systems were typically complex and expensive – some were the size of a large refrigerator. It was not uncommon to see many placed side by side, eating up lots of data center space.
In the past, upgrades meant downtime. Fortunately, modern systems are simpler to manage. They can incorporate solid state devices (SSD) with all-flash arrays becoming the norm. Another innovation is 100% NVMe storage platforms with NVMe over Fabric protocols.
The SAN footprint in the data center has shrunk dramatically, too, courtesy of low-latency, high-density 100% NVMe flash arrays.
SAN Use Cases
- Database acceleration, including traditional (i.e. SQL Server, Oracle, SAP/SAP Hana) and NoSQL (i.e. MongoDB, Cassandra, MariaDB)
- DevOps/DevTest infrastructure for faster software development
- Virtualization and private cloud with VMware, Microsoft, Citrix, Linux, containers and Kubernetes
- Virtualized desktop infrastructure with VMware Horizon, Citrix XenDesktop, Windows Virtual Desktop
- Workload consolidation of virtualized applications, databases, VDI, email, and many industry vertical applications
- Data protection and disaster recovery including targets for snapshots and back-ups
- Policy-based VM-tiering enabled with performance and capacity (cost) optimized targets
- Multi-cloud DevTest – enabled by an efficient platform to store DevTest data and data mobility to the cloud
- Video content storage
How to Select a SAN Vendor
Here are some selection criteria to consider with regard to SAN array procurement:
- Evergreen – Look for SAN solutions that can be non-disruptively upgraded for added capacity, faster performance, or new software capabilities enable customers to avoid three- to five-year hardware refreshes
- Simplicity – Ease of deployment, operations and management are essential in an age when few want to invest in a team of storage management experts. Also, look for automation and integration with leading hypervisor, container, and orchestration platforms via industry standard APIs
- Performance – Fast and consistent performance in the form of low latency and non-disruptively scalable controllers enable businesses to run without disruption, with the performance they need for critical applications
- Efficiency – Data reduction that includes built-in compression, deduplication, and thin provisioning. Depending on the workload,
- Security – This should include built-in encryption of data at rest as well as the ability to encrypt in flight data
- AIOps – AI-generated support and proactive recommendations make sure applications run smoothly, minimize any business disruption, and reduce the need for specialized storage expertise
- Ease of data portability between on-premises and cloud to ensure workloads get consistent enterprise-grade data services.
Top SAN Arrays
Enterprise Storage Forum rates the following among the top SAN arrays, in no particular order:
- Dell EMC PowerMax
- NetApp ASA AFF
- Hitachi Vantara
- Dell EMC PowerStore
- Pure Storage FlashArray
- HPE Primera VSP
- IBM SAN
- Dell EMC PowerVault ME4
Dell EMC PowerMax is the high-end storage offering from the massive Dell storage portfolio. The Dell EMC PowerMax family offers high levels of performance and scale using next-generation Storage Class Memory (SCM) and high-speed SAN infrastructure.
The solution targets mission-critical apps with end-to-end NVMe, real-time machine learning, and a wealth of data services. It also improves storage efficiency with a guaranteed data reduction of almost four to one. San provisioning is said to be possible in less than 30 seconds, plus it offers six nines availability and replication for business continuance and disaster recovery.
- Consolidate block, file and mainframe workloads on one array
- Inline deduplication and compression
- Extreme performance to consolidate demanding mixed workloads
- Automates data placement for optimal performance with no management overhead
- Secure, end-to-end efficient encryption
- Cloud mobility moves data from PowerMax to AWS, Azure, and Dell EMC ECS for long-term retention on lower-cost object storage
- Multi-controller scale-up, scale-out architecture with end-to-end NVMe
- Performance optimized – up to 15M IOPS, 350GB/s sustained bandwidth, under 100µs read latency
Netapp’s all flash FAS (AFF) arrays have an all SAN array (ASA) series known as NetApp ASA AFF. Yes, the naming is confusing. Perhaps it’s because NetApp was initially positioned against the SAN with its Network Attached Storage (NAS) filers in the past.
These days, NetApp offer, SAN, NAS, all flash, everything. NVMe and NVMe-oF protocol specifications are built with the collaboration of operating system, virtualization, and storage vendors and are influenced by engineering and interoperability considerations.
NVMe storage with flexible access over Ethernet transports such as NVMe/TCP and NVMe/RoCE, high IOPS, and low latency can also address modern NoSQL, AI/ML/DL, HPC workloads and distributed file systems in hybrid cloud deployment.
- Low latency storage media – flash/NVMe, SCM, and PMEM deliver orders of magnitude more IOPS compared to magnetic media
- Faster interconnects – 32G FC,100/200/400G Ethernet, and RDMA provide low latency and high bandwidth access to these media
- NVMe and NVMe-oF provide efficient access that can extract orders of magnitude more IOPS from modern storage media at lower latency that demanding applications can leverage to provide more capabilities at higher performance
- Data management features are built over a common foundation across all protocols enabling customers movement of existing SAN workloads to take advantange of NVMe-oF with copyless migration.
The Hitachi Vantara Virtual Storage Platform (VSP) includes the G series, F series, VSP 5000 series, and VSP E990.
The VSP 5000 is available as all-flash or a combo of flash and disk. The VSP E990 is more of a midrange storage array. Both support NVMe SSDs and SCM Hitachi Vantara’s high-end and midrange storage systems leverage a common architecture and operating system, providing a simplified management and protection experience.
- 100% data availability
- 4:1 effective capacity
- AI-powered software tools within Hitachi Ops Center simplify management and improve IT operational efficiencies
- Scales to 69 PB and 21M IOPS.
- Up to eight 9’s of availability
- Supports RAID 1, 5, and 6
Dell EMC PowerStore is Dell’s midrange storage platform that is designed to address any workload. It’s single architecture for block, file, and VMware vVols supports both traditional and modern workloads – from relational databases and ERP, to cloud native applications and file-based workloads such as content repositories and home directories.
The solution also supports physical, virtual, and container-based apps and databases on one array with “6 9s” availability. This array can scale up and scale out, and IT can independently add capacity or processing power.
- The only storage array on the market to feature a VMware ESXi hypervisor
- Administrators can deploy apps directly on the array for greater flexibility
- AppsON for data-intensive workloads in core or edge locations and infrastructure applications
- Consolidate block, file, and VMware vVols
- Its end-to-end NVMe design is said to be up to 7X faster than previous arrays with up to 3X better response time
- Inline data reduction of 4:1 average
Pure Storage offers two arrays. The FlashArray//X is aimed at high performance while the FlashArray//C is the high capacity version. It’s a case of which attribute is favored in the enterprise, or required more by the application and environment.
The company promotes the FlashArray//X as the world’s first 100% all-flash end-to-end NVMe and NVMe-oF array. These arrays serve needs ranging from departmental to large-scale enterprise deployments. They provide performance, reliability, and availability for mission-critical operations—both block and file. The FlashArray//C is more about consolidating workloads with consistent all-flash NVMe performance and data protection.
- Evergreen Storage eliminates upgrade cycles, downtime and rebuys of TBs already owned. The Evergreen Storage subscription model offers rapid upgrades and expansion without disruption
- Always on deduplication, compression, and thin provisioning
- Low-latency performance for all workloads, including: sub-1 ms latency performance for mission critical workloads, up to 150 ms latency for extreme database workloads with storage class memory, and consistent 2-4 ms latency for capacity optimized workloads
- 9999% availability as well as business continuity and global disaster recovery
- Consistent data portability between on-premises and public cloud storage and applications to minimize complexity and simplify interoperability
Like Dell, Hewlett Packard Enterprise (HPE) is one of these vendors that have accumulated a lot of different storage array vendors over the years. Its portfolio includes HPE Primera, Nimble Storage, 3PAR and XP series, some of which are the remains of storage and SAN startup pioneers.
Primera targets high-end storage array targeting Tier 0 and Tier 1 mission-critical workloads. Nimble Storage is mainly for the midrange. HPE storage arrays include support for NVMe media, peer persistence, SCM, VMware vVOLs, Kubernetes, and container automation.
- AIOps data platform based on InfoSight for automation and integration across HPE assets as well as fault-detection
- Workload mobility across hybrid cloud assets
- GreenLake consumption-based offering provides inclusive software licensing, flexible asset ownership and nondisruptive future upgrades and refreshes.
- 100% availability guarantee
- Analyze and predict disruptions across the infrastructure stack.
IBM continues to provide traditional SAN switches and directors while also embracing newer technologies such as all flash in its FlashSystem and hybrid arrays. There are a great many arrays to choose from such as the high-end DS8900F for primary storage workloads.
The entire product portfolio utilizes a common storage operating system, common APIs and common management to simplify integration and architectural design. They are also easy to integrate with the massive family of IBM hardware, middleware, and software offerings.
- Key Differentiators
- Abundance of system memory to increase cache hit ratio and improve workload consolidation
- High-capacity flash drives
- Write support for Global Mirror primary devices
- Secure data transfer for transparent cloud tiering
- Transparent cloud tiering.
The Dell EMC PowerVault ME4 Series is more aimed at affordability, lacking the extreme performance of some of the higher-end arrays. It provides SAN and Direct Attached Storage (DAS) and is optimized to run a variety of mixed workload applications – physical and virtual – mainly for small and mid-sized businesses.
DAS can be used to consolidate block storage, support data intensive applications, take advantage of intelligent data management, or optimize virtual environments. Additional storage capacity can be added via Disk Array Enclosures. Also comes with distributed RAID for faster drive re-build times.
- Intelligent data management
- IT can decide which protocol to run
- Supports a wide range of mixed drive types
- Scales to 4 PB raw
- Alignment with Dell PowerEdge Servers provides easy integration and infrastructure design
- Based on Intel Broadwell-DE processors
- Dell EMC PowerVault ME4 Series storage implements a block architecture with VMware virtualization integration and concurrent support for native iSCSI, Fibre Channel, and SAS protocols
- Each system leverages dual storage processors (single storage processor systems are available) and a full 12Gb SAS back-end.