All posts by Guest Blogger

Why iSER is the right high speed Ethernet all-flash interconnect today

The following is a guest blog post from Subhojit Roy, a Senior Technical Staff Member working out of IBM India Labs. 

All-flash storage is bringing change throughout the data center to meet the demands of modern workloads. Fiber Channel has traditionally been the preferred interconnect for all-flash storage. However, 21st century data center paradigms like cloud, analytics, software defined storage, etc. are driving a definitive shift towards Ethernet infrastructure that includes Ethernet connectivity for both server and storage. As Ethernet speeds rapidly increase to 25/40/50/100Gb, it becomes more and more lucrative as an interconnect to all-flash storage. While traditional iSCSI has gained significant ground as Ethernet interconnect to storage, inefficiencies in the TCP/IP stack don’t allow it to be the preferred interconnect to all flash storage.

In comes iSER (iSCSI Extensions over RDMA) that maps the iSCSI protocol to RDMA (Remote Direct Memory Access). iSER provides an interconnect that is very capable of rivaling Fiber Channel as the all-flash interconnect of choice. It leaves the administrative framework of iSCSI untouched while mapping the data path over RDMA. As a result, management applications like VMWare vCenter, OpenStack, etc. continue to work as is, while the iSCSI data path gets a speed boost from Remote Direct Memory Access. A move from traditional iSCSI to iSER would thus be a painless affair that doesn’t require any new administrative skills.

iSER retains all the enterprise class capabilities that are expected off Tier 1 shared storage. It also matches or beats Fiber Channel in terms of access latency, bandwidth and IOPS. Capabilities like multipath IO, SCSI Reservations, Compare and Write, vVols support, and offloaded data copy operations like XCOPY/ODX will work from day one on iSER. In addition, iSER benefits from all the SCSI error recovery techniques that have evolved over the years – things like LUN Reset, Target Reset, Abort Task, etc. In essence, all enterprise class applications will continue to work as reliably and seamlessly over iSER as they used to work over iSCSI.

The diagram below shows how iSCSI is involved in the iSER IO path only for the Command and Status phases while the Data Transfer phase is totally taken care of by RDMA transfers directly into application buffers without involving a copy operation. This compares well with NVMeF in terms of latency reduction.

NVMe over Fabrics or NVMeF is a new protocol that promises to take all-flash interconnect technology to the promised land of extreme performance and parallelism and there are a lot of expectations from it. It is a protocol that is still evolving, and therefore not mature enough to meet the requirements of clustered applications running over shared Tier 1 all-flash storage. And it is a quantum jump that not only expects the user to move to high speed Ethernet technology from Fiber Channel but a totally new protocol with a new, unfamiliar administrative model. It is likely that NVMeF will take some time to mature as a protocol before it can be accepted in data centers requiring Tier 1 shared all-flash storage. In addition to that applications must adapt to a new queuing model to exploit the parallelism offered by flash storage.

That leaves iSER as the right technology to bridge the gap and step in as the preferred interconnect for shared all-flash storage today. iSER is ready from day one for latency, IOPS and bandwidth hungry applications that want to exploit high speed Ethernet technology, both as a north-south and east-west interconnect. IO parallelism may not be as high as promised by NVMeF, but it’s sufficient for all practical purposes without requiring applications to be rewritten to fit into a new paradigm.

By implementing iSER today, the move from Fiber Channel to high speed Ethernet can be tried out without ripping out the entire administrative framework or the need to rewrite applications. A gradual move from Fiber Channel to RDMA over Ethernet replaces the layer 2 transport protocol and helps assess the newer protocol in terms of its stability, resiliency and error recovery capabilities that are essential for a SAN storage interconnect. Once proven, the same RDMA technology can then be leveraged to bring in NVMeF which promises more in the future. Since iSER and NVMeF will work equally well on the same hardware, the infrastructure investment made in iSER is protected for the long term.

At IBM we are working toward enabling our customers to move to data center infrastructure that consists purely of Ethernet interconnects with speeds scaling rapidly from 10 – 100Gbps. Built over iSER, this capability is all-flash storage ready from day one. Agnostic of the underlying RDMA capable networking, it is likely to be very attractive to software defined storage infrastructure that is expected to be built from commodity hardware. It enables IBM Spectrum Virtualize products (IBM Storwize and IBM SVC) to be deployed on cloud infrastructure where Ethernet is the only available infrastructure. And in order to get there, we have partnered with multiple hardware and software vendors that are at the forefront of the high speed Ethernet revolution.

So get ready to experience all-flash storage connected over high speed Ethernet from IBM sometime in the near future!

Subhojit is Senior Technical Staff Member working out of IBM India Labs, Pune. He works as development architect for the IBM Spectrum Virtualize product. He has worked for 23 years in Data Storage, Storage Virtualization, Storage Networking etc. across organizations like IBM, Veritas, Brocade & Symantec etc. At IBM he has been driving Ethernet & IP Storage architecture and roadmap for the IBM Spectrum Virtualize products. Currently he is working on high speed Ethernet interconnect for all flash storage including iSER and NVMeF. Prior to IBM he has been responsible for key features for Enterprise Storage products in his earlier organizations. He is Master Inventor and Member Academy of Technology at IBM. He owns significant Intellectual Property in the form of patents and has more than 50 granted and filed patent applications. He can be found on Twitter @sroy_sroy and on LinkedIn at


RDMA enhancements for ISCSI

Guest post by Noam Shendar, VP Business Development, Zadara Storage

Just Punch It:  Accelerating Storage the Easy Way

Architecting storage solutions means being on the hunt for bottleneck after bottleneck and removing them to eliminate latency wherever possible. With the availability of storage media such as Flash and high-performance disk drives, the bottleneck has often moved away from the storage medium itself and onto the interconnect.


When building our enterprise storage as a service offerings, we’ve had to overcome several bottlenecks – from reinventing the proprietary, purpose-built controllers of traditional arrays that caps the speed and expandability of an array, through the performance of the controllers, to using flash cache acceleration, it was clear that to deliver applications with even better efficiency our award-winning Virtual Private Storage Arrays (VPSA) need to take advantage of new technologies for the datapath.


What is iSER technology?

iSER is an interface that uses Ethernet to carry data directly between server memory and storage devices. The protocol eliminates memory copies (a.k.a. memcpy) and the operating system TCP/IP stack, and bypasses the CPU of the target system entirely.  As such, it is lossless, deterministic, with low overhead, and delivers far better CPU efficiency by freeing up resources.

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End of an Era: OEM Dominance – Could it Be a Thing of the Past?

Guest Blog post by Giacomo Losio, Head of Technology – ProLabs

Original equipment manufacturers (OEM’s) have long dominated the optical components market but a new study now suggests that, as a result of tighter margins and greater competition, customers are putting quality and price before brand.  Is the era of the big OEM at an end?

When asked their views of the optical transceiver market at the European Conference on Optical Communications (ECOC) in Cannes, over 120 attendees revealed a trend which indicates a paradigm shift in attitudes.

Why do they buy? What they buy? What keeps them up at night? The answers may surprise you:

  • 98% of respondents ranked quality as one of their top three priorities when purchasing fibre optics
  • 89% of respondents placed price in the top three list of priorities
  • Yet only 14% of respondents even considered brand names to be a top three priority – or even a concern

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The Benefits of Leaning Into the Big Data

Guest post by Alex Henthorn-Iwane, QualiSystems

Big data is for real, but its places heavy demands on IT teams, who have to pull together and provision cloud infrastructure, then offer big data application deployments with validated performance to meet pressing business decision timelines.  QualiSystems is partnering with Mellanox to simplify big data deployments over any cloud infrastructure, enabling IT teams to meet line of business needs while reducing operational costs.

Quali Systems cutcaster-903282828-Big-data-small

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The Storage Fabric of the Future Virtualized Data Center

Guest post by Nelson Nahum, Zadara Storage

It is evident that the future data center will be based on cutting-edge software and virtualization technologies to make the most effective use of hardware, compute power, and storage needs to perform essential analytics and to increase the performance of media-related and advanced web applications. And it turns out that the wires that will connect all this technology together are no less crucial to next-generation data centers and clouds than the software and virtualization layers that run within them.

There are multiple storage fabrics and interconnects available today, including Fibre Channel, Ethernet and SAS. Each has various pros and cons, and fabrics were chosen according to need of performance, compatibility and cost efficiencies.


As an enterprise storage as-a-service provider, delivering a software-based cloud storage solution for public, private and hybrid cloud models based on commodity hardware, Zadara Storage provides storage as-a-service in multiple public cloud and colocation facilities around the globe. Consistency, high availability and predictability are key in supplying the scalable, elastic service our customers expect, regardless of their location, facility or the public cloud they employ. The hardware we use needs to be dependable, pervasive and cost-efficient in order to sustain the performance and cost-level of our service, anywhere and at any scale.


When choosing our fabric, Ethernet came as a clear choice. Ethernet is likely to become the new standard, and boasts several advantages vital to our product:

  • Ethernet’s speed roadmap is aggressive: from 10GbE to 40GbE, and upcoming 100GbE
  • Ethernet is ubiquitous: we can employ it with no complication at any data center or colocation facility around the globe
  • The latency we have found to be more than manageable, specifically as we use advanced techniques such as IO virtualization and data passthrough
  • Ethernet is the most cost effective: an as-a-service company needs to have a competitive pricing edge.

The future of enterprise storage
The future of Enterprise Storage lies in software and a choice of hardware (premium or commodity). Software-defined storage can scale performance more easily and cost effectively than monolithic hardware, and by combining the best of hardware of software, the customer wins. Ethernet is a critical element of our infrastructure, and Mellanox switches offer significant higher performance and consistent dependability that enables our storage fabric and meets our customer’s needs.


Zadara Storage at the Mellanox Booth at VM World 2013
Wednesday, August 28, at 2:15pm
At the Mellanox Booth at VM World 2013, Zadara Storage CEO, Nelson Nahum, will present the Zadara™ Storage Cloud, based on the patent-pending CloudFabric™ architecture, and providing a breakthrough cost structure for data centers. Zadara’s software-defined solution employs standard, off-the-shelf x86 servers, and utilizes Ethernet as its only interconnect to provide performant, reliable, SSD- and spindle-based SAN and NAS as a service.


About Zadara Storage
An Amazon Web Services and Dimension Data Technology Partner and winner of the VentureBeat, Tie50, Under the Radar, and Plug and Play cloud competitions, Zadara Storage offers enterprise-class storage for the cloud in the form of Storage as a Service (STaaS). With Zadara Storage, cloud storage leapfrogs ahead to provide cloud servers with high-performance, fully configurable, highly available, fully private, tiered SAN and NAS as a service. By combining the best of enterprise storage with the best of cloud and cloud block storage, Zadara Storage accelerates the cloud by enabling enterprises to migrate existing mission-critical applications to the Cloud.