Dell EMC Unity vs. HPE Nimble

Comparing The Conglomerate Giants of Hybrid and All-Flash Storage Arrays

The 21st century demands storage. Companies of all types and sizes are scrambling to reckon with the ever-increasing storage needs of digital business. This means growth, an emphasis on scalability and keeping costs down. Dell EMC’s Unity and HPE’s Nimble promise to solve these needs, both delivering compact, hybrid/all-flash and multi-purpose storage solutions. The two conglomerates run neck and neck as the largest enterprise storage vendors on the market, each with 2Q18 revenues over $2 billion.*  

The short version is that both products will perform. Nimble has a more advanced software management interface that delivers predictive analytics and an accelerated read/write protocol. Dell EMC Unity offers options for block/file level storage and more comprehensive API support.  

Fundamentally, if your existing storage infrastructure is already dominated by Dell EMC or HPE products, you will find it easier to stick within that ecosystem. Both products work better within their own environments, and neither offers such a revolutionary advantage over the other that it is worth causing disruption. If starting from scratch, however, it is worth weighing up the pros and cons. That is what we will do here.  

HPE Nimble: SAN Storage and Predictive Management

Nimble was founded in the late 2000s and purchased by HPE in 2016.* Entering the market as a ground-up hybrid storage system, Nimble has been a market disruptor from the beginning. Their focus has always been to deliver unified control over all-flash, adaptive flash, hybrid arrays and cloud storage. Nimble enables easy on-ramping to HPE’s Cloud Volumes — an enterprise-grade, multi-cloud storage solution from AWS and Azure.

Downsides: No NAS Options

Nimble’s main limitation is that it is a SAN only ‘block storage’ solution. Nimble cannot be configured as a NAS. In NAS, ‘file level’ storage protocols allow you to save files and access them directly. Block level SAN storage means that information is saved in blocks and an interfacing program is needed for access.

Fundamentally, NAS is a simpler system to operate. But, SANs can move large chunks of data between servers and devices faster and with greater security. Data is more easily controlled and segregated, and multiple servers can be used to access a single pool of resources. You can even connect multiple servers to your SAN and designate particular tasks or access capabilities to each, but use excess power from any given server to aid processes undertaken elsewhere in the network.  

SANs have long been the ‘premium’ solution for enterprise customers. Ten years ago, interfacing with block level storage might have been a concern for small businesses. But, Windows and Linux both deliver file services as standard. The now near universal access to CIFS, NFS and SMB interfaces make using block storage about as easy as file storage. But, if you are committed to NAS only architecture, Nimble is not your solution.    

Upsides: InfoSight and CASL

Nimble delivers two great assets: InfoSight and CASL. InfoSight is Nimble’s Cloud based Analytics Platform. It enables predictive analytics that Nimble claims will make ‘86% of your problems disappear’ by optimising storage management and support. The system collects millions of data points a minute to designate usage of SSD, HDD and Cloud components and automate system maintenance tasks.

Machine learning algorithms allow the system to take actions independently, only alerting operators for serious problems.* InfoSight can now interface with HPEs 3PAR hardware. For an HPE only network, this delivers complete system visibility and the ability to virtually troubleshoot your network for the easy identification of failures.

Nimble’s CASL operating system (Cache Accelerated Sequential Layout) is a write system based loosely on Journal File System technology. CASL achieves faster speeds by storing data and metadata on a ‘transcription log’. This log is stored locally on high-speed flash or NVRAM, before being transferred to a final destination on the main system.

The caching of that data on high-speed local memory accelerates subsequent access to data when actively working with an application. The slower ‘transfer’ process can be done at a point when demand for processing power is low. Effectively, this allows hybrid Nimble arrays to function at the speed of flash most of the time, while still storing data on cheap disks. This keeps total storage costs down while improving access speeds.

The value of this technology, however, is reduced if you access programs in a sequential order and/or do not require repeated access to the same data. Applications have to be spun up from HDD the first time they are accessed and are only available on flash during subsequent reads/writes.   

CASL always writes data in a new place. This means that some data already on the system will be invalidated by later writes, creating an additional task of ‘garbage collection’ — going through to clean up redundancies. This is something that can be done when demand on the system is low, essentially how defragmentation should occur. But, it is an extra task that your network will need to accommodate. However, if the way you access data allows you to take advantage of CASL’s speed benefits, the system provides a powerful advantage to hybrid storage ecosystems.     

Dell EMC Unity: A New Beginning For An Old Leader

EMC was an early developer of memory boards, but became an industry leader with their revolutionary enterprise storage product Symmetrix developed during the 1990s. In 2015, EMC was acquired by Dell for $67 billion (still considered the largest tech-industry acquisition in history) creating Dell EMC as a subdivision of Dell Technologies.

Upsides: Fast, Improved and Unified Storage

Unity is the mid-range storage product in the Dell EMC lineup. Introduced in 2016, it is marketed as a ‘ground up’ storage array designed for the flash focused data centre. In reality, it is an upgraded version of their legacy VNX products that Unity was designed to replace. That, however, does not speak poorly of the system. Metrics based analysis indicate 3x performance over the previous generation VNX arrays which were themselves a market leading storage solution.*

These performance improvements are the result of some fundamental changes to the system. VNX units always functioned as entities with separate parts — combining the existing Clariion and Celerra technology to provide SAN block storage and NAS file storage separately. For Unity, the NAS component has been virtualised. This simplifies hardware setup and allowing for the ability to upgrade file-system support.   

Unity is a truly unified storage array. Unlike Nimble products, Unity delivers both SAN and NAS options. Unity is quick to install, easy to integrate into existing infrastructure and comes in all-flash and hybrid configurations at a range of sizes.

There are also the UnityVSA and UnityVSA Cloud options. These bring the features of Unity storage to the cloud and VMware virtualised environments. Users are able to easily scale onto the public cloud through Amazon Web Services (AWS) or VMware SDDC (Software-Defined Data Centre). Unity VSA Cloud also supports disaster recovery syncing between Unity systems and VMware cloud-based applications.

Downsides: Weak Management Tools … Unless You Like REST APIs

Dell EMC Unity comes with a proprietary management tool — Unisphere. Unisphere is a quality option, it just isn’t as good as InfoSight. However, this might not matter.

Unisphere does not offer the same level of automated and predictive maintenance, Application Performance troubleshooting etc. It does, however, offer you a unified point of control over all of your Dell EMC products and allows you to virtually troubleshoot your storage system. The benefits of Nimble’s CASL are reduced in all-flash storage environments, or when data is only accessed sequentially for single instances. The specifics of your ecosystem will determine the importance of these differences.

Dell EMC also offers native support and integration for REST APIs. REST APIs are a popular tool in data centres to standardise the management of ecosystems built from multi-vendor components.* They depend on HTTP operations like GET, POST and DELETE. If you already use or like this system, then this native support is great. But, it isn’t anything new, it does not offer a native GUI interface and does not provide an intuitive experience for inexperienced operators. The ability of a REST API system to deliver the type of visibility and maintenance capabilities made easy by Unisphere is dependent on the skill of the operator. Reaching InfoSight levels of predictive analytics is likely out of the reach of any REST API system.  

Unity vs. Nimble: Don’t Forget About VMware and Hypervisors

Both InfoSight and Unisphere are capable of integrating with VMware. There are a number of reason that data centres embrace virtualisation technology. Perhaps the main reason is to create a unified storage environment in which hardware from multiple vendors can be utilised centrally.

Infosight, particularly, has an advanced plugin that will collect data from your VMware environment and assess it with the same level of insight as it can deliver to Nimble and 3PAR hardware. Unisphere will also integrate seamlessly with VMware virtualised environments. However, what that delivers will still be limited compared to the advanced analytics and write protocols of InfoSight. But, Unisphere will provide an intuitive provisioning and control interface.

For both products, access to this universal and ‘hardware-agnostic’ control system requires investment in VMware virtualisation technology.

Summary: Dell EMC Offers Unified SAN and NAS Solutions, Nimble Delivers Predictive Management  

Dell EMC Unity hardware delivers more configuration options, allowing you to use both block and file level storage. Nimble’s selling point is its advanced software management solution. InfoSight is truly one of the most powerful software management solutions available in the storage market. Even NetApps ONTAP 9 struggles to compete. CASL accelerates write procedures, Infosight introduces machine learning proactive/predictive maintenance and improves storage visibility. Unisphere delivers visibility. However, it cannot match InfoSight in the other categories.*

What Dell EMC does offer, however, is native integration and support for REST APIs. If you are already using this system to control your storage environment, Unity is the clear choice. Equally, if the features offered by InfoSight are unimportant to how you run your storage ecosystem, many of the reasons to purchase Nimble products are diminished.

The ability delivered by CASL to use a hybrid storage environment at the speed of flash under most circumstances is a powerful option to increase performance and keep costs down. If starting from scratch, building an array of hybrid Nimble drives empowered by InfoSight is a cost-effective way to access storage that will give you 90% of the performance of an all-flash array. If you have a storage environment dominated by Dell EMC products, Unity is a great and easy way to expand your storage capabilities. Both solutions offer quality and easy to use hardware, VMware integrations and intuitive control interfaces.   

Sources:

*Worldwide Enterprise Storage Systems Market Revenue Grew 21.3% During the Second Quarter of 2018, According to IDC
*Why did Nimble sell and why did HPE buy: We drill into $1.2bn biz deal
*Gulp. HPE’s InfoSight self-repairs and makes ‘proactive decisions’
*EMC Unity or VNX3? You tell me
*Dell EMC Unity: Unisphere Overview
*Dell EMC Unity vs. Nimble Storage