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    Storage Expert Takes on Hyperconverged Questions

    April 17th, 2017

    Last month, we were fortunate enough to have Greg Schulz, analyst and founder of Server Storage IO, as a guest speaker at our SNIA Ethernet Storage Forum webcast, “What Does Hyperconverged Mean to Storage.” If you missed it, it’s now available on-demand. Greg fielded many great questions during the live event, but we didn’t have time to get to them all. So here they are:

    Q. What is the difference between Converged Infrastructure (CI) and Hyperconverged Infrastructure (HCI)?

    A. HCI is aggregated. You scale compute and storage in lock step. Converged is disaggregated. You can scale the compute independently of the storage. There are some software solutions that can support both hyper-converged (aggregated) and converged (disaggregated) deployments.

     Q. What is your definition of “Little Data”?

    A. Little Data is anything that’s not Big Data. It encompasses traditional databases, traditional structured, semi-structured and even some unstructured data.

    Q. With convergence, what is the impact on the IT organization?

    A. There is an opportunity for organizations to converge how they manage data infrastructure resources and services delivery. In other words, the technology can be leveraged to help an organization itself converge. Another impact is how converged solutions are protected, backed up, BC/BR/DR and related management done. Traditionally there are separate IT teams for compute, storage, and networking, especially in a large organization. New technology solutions may allow an organization to converge those teams.

    Q. Is there a hybrid strategy? Where a complete information system is composed of HCI/CI building blocks? If yes, what management tools would span these components?

    A. Sure, why not? Certainly you can converge your environment into a particular CI/HCI solution or approach, likewise, different CI/HCI solutions can co-exist along with other solutions in a given environment in hybrid ways. Have a hybrid strategy that looks at how technologies and solutions adapt to your needs and environment. Focus on how it’s going to work for you, vs. you having to work for them.

    Q. What does FUZE stand for?

    A. FUZE is not an acronym. It is the actual fuzing as in melding and bringing together things – literally fuzing thing together.

    Q. Do HCI vendors re-balance (compute, I/O, storage) automatically as more nodes are added?

    A. Solutions vary in how they rebalance the workloads. Some are dynamic while others rebalance on intervals; it varies how, when and what they rebalance. So, as you add capacity as you make changes, you need to make sure resources are properly allocated to address performance.

    Q. Can’t you offload those CPU cycles caused by I/O to another CPU?

    A. That’s an interesting question. Yes, move the application to another CPU. There is software that will leverage the resources on another CPU. Most HCI and CI solutions are running on a stack that requires hardware somewhere.

    Q. This discussion has touched on compute and storage scaling. What about network between compute in the CI/HCI infrastructure and external to other compute, databases, or end-users?

    A. Both CI and HCI need to connect to other resources, but in most cases the highest levels of network traffic are inside the CI or HCI stack because the compute and storage resources are contained within. Their connections to outside clients or servers data exchange, application integration, or client access is important but usually not very demanding on network bandwidth. (External connections for storage remote replication or backup could be bandwidth-intensive.)

    Q. How can the current Enterprise Storage Products blend with either CI or HCI? Enterprise Storage is basically centralized storage architecture however the HCI is built mostly on ‘distributed storage architecture’. So how can current Enterprise Storage show use cases to the customer to sell their Enterprise Storage either as part of the HCI solution or exist along with HCI?

    A. Generally enterprise storage products can be included in CI but are not blended with HCI. For example Dell EMC, Cisco (with NetApp and other storage vendors), IBM and Oracle offer CI solutions that include enterprise storage arrays in the rack. Most HCI platforms do not interoperate with enterprise storage arrays because the HCI platforms include their own storage. They can co-exist with enterprise storage arrays and that’s how most customers deploy them—some workloads run on the HCI infrastructure while others continue to use enterprise storage arrays.

    Q. One of the HCI selling points is simplicity and cost reductions from a la carte. It seems that from what is being presented, that may not be the case. Can you elaborate on where HCI may become more complex, costly?

    A. It comes down to value. You can buy all the components yourself and glue them all together and may come up with a lower total cost, but what is the value of your time? What is the cost of staff time to evaluate, test, deploy and maintain. The total value must be considered. It’s possible that HCI will be more costly than a disaggregated deployment that separates compute and storage, but this depends heavily on the workload and specific vendor product solution implementation.

    Q. Current HCI “full stack” solutions claim compute and storage convergence, but what about the network? Given the east/west traffic introduced by HCI solutions, what networking solutions should customers be looking at?

    A. Most of the common HCI solutions are packaged with server, storage, compute and most have networking included as well—typically the network adapters and sometimes also the switches. Some even have a backend software defined networking (SDN) capability as part of their stack.

    Q. Related to HCI answer, what about vendors who allow for storage growth and/or server (compute) and storage additions. This allows for aggregated and dis-aggregated…yes?

    A. Most HCI vendors require compute and storage to be added simultaneously, though many support different nodes with different ratios of compute and storage. This allow customers to change the ratio of compute and storage by adding different node types. And yes, some HCI vendors also support both a hyper-converged and disaggregated model, with the disaggregated model allowing compute and storage to be added separately.

    Q. What are the tools available to make HCI work in a hybrid load environment, with different workload requirements, e.g.: VDI and Databases?

    A. There are tools for moving and migrating applications, workloads, systems and VMs into CI/HCI environments, likewise for tuning, optimizing, gaining insight, analytics and reporting. Most of the CI/HCI solutions have tools built into them for optimizing PACE (Performance, Availability, Capacity, Economics) attributes along with server compute, memory, storage, and I/O resources. Some CI/HCI solutions are optimized for VDI/workspaces, while others are able to support general workloads including databases, and some even support HPC/SC or other specialized workloads.

    Q. Does network performance affect HCI or CI performance?

    A. Sometimes. Most hybrid HCI nodes are happy with the bandwidth of 10GbE, but if the nodes are all-flash or have many disks, then a faster speed may be required to avoid a network bottleneck. Network latency could affect HCI or CI performance in some cases, especially with all-flash storage. Of course a reliable network helps ensure reliable CI/HCI operations.

     


    SNIA Ranked #2 for Storage Certifications – and Now You Can Take Exams at 900 Locations Worldwide

    March 29th, 2017

    The SNIA Storage Networking Certification Program (SNCP) provides a strong foundation of vendor-neutral, systems-level credentials that integrate with and complement individual vendor certifications. Its four credentials – SNIA Certified Storage Professional; SNIA Certified Storage Engineer; SNIA Certified Storage Architect; and SNIA Certified Storage Networking Expert  – reflect the advancement and growth of storage networking technologies, and establish a uniform standard by which individual knowledge and skill sets can be evaluated, thereby providing employers in the storage industry with an independent assessment of the individual.… Continue reading


    Latency Budgets for Solid State Storage Access

    March 7th, 2017

    New solid state storage technologies are forcing the industry to refine distinctions between networks and other types of system interconnects.  The question on everyone’s mind is: when is it beneficial to use networks to access solid state storage, particularly persistent memory?

    It’s not quite as simple as a “yes/no” answer. The answer to this question involves application, interconnect, memory technology and scalability factors that can be analyzed in the context of a latency budget.

    On April 19th, Doug Voigt, Chair SNIA NVM Programming Model Technical Work Group, returns for a live SNIA Ethernet Storage Forum webcast, “Architectural Principles for Networked Solid State Storage Access – Part 2where we will explore latency budgets for various types of solid state storage access. These can be used to determine which combinations of interconnects, technologies and scales are compatible with Load/Store instruction access and which are better suited to IO completion techniques such as polling or blocking.

    In this webcast you’ll learn:

    • Why latency is important in accessing solid state storage
    • How to determine the appropriate use of networking in the context of a latency budget
    • Do’s and don’ts for Load/Store access

    This is a technical seminar built upon part 1 of this series. If you missed it, you can view it on demand at your convenience. It will give you a solid foundation on this topic, outlining key architectural principles that allow us to think about the application of networked solid state technologies more systematically.

    I hope you will register today for the April 19th event. Doug and I will be on hand to answer questions on the spot.


    Clearing Up Confusion on Common Storage Networking Terms

    January 12th, 2017

    Do you ever feel a bit confused about common storage networking terms? You’re not alone. At our recent SNIA Ethernet Storage Forum webcast “Everything You Wanted To Know About Storage But Were Too Proud To Ask – Part Mauve,” we had experts from Cisco, Mellanox and NetApp explain the differences between:

    • Channel vs. Busses
    • Control Plane vs. Data Plane
    • Fabric vs. Network

    If you missed the live webcast, you can watch it on-demand. As promised, we’re also providing answers to the questions we got during the webcast. Between these questions and the presentation itself, we hope it will help you decode these common, but sometimes confusing terms.

    And remember, the “Everything You Wanted To Know About Storage But Were Too Proud To Ask” is a webcast series with a “colorfully-named pod” for each topic we tackle. You can register now for our next webcast: Part Teal, The Buffering Pod, on Feb. 14th.

    Q. Why do we have Fibre and Fiber

    A. Fiber Optics is the term used for the optical technology used by Fibre Channel Fabrics.  While a common story is that the “Fibre” spelling came about to accommodate the French (FC is after all, an international standard), in actuality, it was a marketing idea to create a more unique name, and in fact, it was decided to use the British spelling – “Fibre”.

    Q. Will OpenStack change all the rules of the game?

    A. Yes. OpenStack is all about centralizing the control plane of many different aspects of infrastructure.

    Q. The difference between control and data plane matters only when we discuss software defined storage and software defined networking, not in traditional switching and storage.

    A. It matters regardless. You need to understand how much each individual control plane can handle and how many control planes you have from a overall management perspective. In the case were you have too many control planes SDN and SDS can be a benefit to you.

    Q. As I’ve heard that networks use stateless protocols, would FC do the same?

    A. Fibre Channel has several different Classes, which can be either stateful or stateless. Most applications of Fibre Channel are Class 3, as it is the preferred class for SCSI traffic, A connection between Fibre Channel endpoints is always stateful (as it involves a login process to the Fibre Channel fabric). The transport protocol is augmented by Fibre Channel exchanges, which are managed on a per-hop basis. Retransmissions are handled by devices when exchanges are incomplete or lost, meaning that each exchange is a stateful transmission, but the protocol itself is considered stateless in modern SCSI-transport Fibre Channel.

    iSCSI, as a connection-oriented protocol, creates a nexus between an initiator and a target, and is considered stateful. In addition, SMB, NFSv4, ftp, and TCP are stateful protocols, while NFSv2, NFSv3, http, and IP are stateless protocols.

    Q. Where do CIFS/SMB come into the picture?

    A. CIFFS/SMB is part of a network stack.  We need to have a separate talk about network stacks and their layers.  In this presentation, we were talking primarily about the physical layer of the networks and fabrics.  To overly simplify network stacks, there are multiple layers of protocols that run on top of the physical layer.  In the case of FC, those protocols include the control plane protocols (such as FC-SW), and the data plane protocols.  In FC, the most common data plane protocol is FCP (used by SCSI, FICON, and FC-NVMe).  In the case of Ethernet, those protocols also include the control plan (such as TCP/IP), and data plane protocols.  In Ethernet, there are many commonly used data plane protocols for storage (such as iSCSI, NFS, and CIFFS/SMB)


    SNIA Storage Developer Conference-The Knowledge Continues

    October 13th, 2016

    SNIA’s 18th Storage Developer Conference is officially a success, with 124 general and breakout sessions;  Cloud Interoperability, Kinetiplugfest 5c Storage, and SMB3 plugfests; ten Birds-of-a-Feather Sessions, and amazing networking among 450+ attendees.  Sessions on NVMe over Fabrics won the title of most attended, but Persistent Memory, Object Storage, and Performance were right behind.  Many thanks to SDC 2016 Sponsors, who engaged attendees in exciting technology discussions.… Continue reading


    Outstanding Keynotes from Leading Storage Experts Make SDC Attendance a Must!

    September 18th, 2015

    Posted by Marty Foltyn

    Tomorrow is the last day to register online for next week’s Storage Developer Conference at the Hyatt Regency Santa Clara. What better incentive to click www.storagedeveloper.org and register than to read about the amazing keynote and featured speakers at this event – I think they’re the best since the event began in 1998! Preview sessions here, and click on the title to download the full description.… Continue reading


    Ethernet Roadmap for Networked Storage Q&A

    July 17th, 2015

    Almost 200 people attended our joint Webcast with the Ethernet Alliance: “The 2015 Ethernet Roadmap for Networked Storage.” We had a lot of great questions during the live event, but we did not have time to answer them all. As promised, we’ve complied answers for all of the questions that came in. If you think of additional questions, please feel free to comment on this blog.

    Q. What did you mean by parity of flash with HDD?

    A. We were referring to the O’Reilly article in “Network Computing.”  O’Reilly is predicting parity in BOTH capacity and price in 2016.

    Q. When do we expect IEEE standards ratification for 25G speed?

    A. 2016.  You can see the exact schedule here.

    Q. Do you envision the Enterprise, Cloud Providers, HPC, Financials getting rid of their 10/40GbE infrastructure and replacing that with 25/100GbE infrastructure in 2017? Will these customers deploy 100GbE/25GbE switch in the leaf layer in 2017?

    A. Deployment will occur over a multi-year time span overall if only because switch infrastructure is expensive to upgrade, as reflected in the Crehan Research forecast.  New deployments will likely move to 25/100GbE as new switches with 100GbE downstream ports become available in 2016.   Just because the Cloud Service Providers are currently the most aggressive in driving new infrastructure purchases, they represent the largest early volumes for 25/100 GbE.  Enterprise is still in the midst of the transition from 1GbE to 10GbE.

    Q. What are some of the developments on spanning-tree derivatives vs. Dykstra based derivatives such as OSPF, FSPF for switches?

    A. Beyond the scope of this presentation on Ethernet.  Ethernet is defined by the IEEE for L1 and L2 in the ISO model.  Your questions are at L3 and L4, which is handled by organizations like IETF.

    Q. With all the speeds possible who is working on flow control?

    A. Flow control at the 802.1 level is supported in the Layer 1/2 PHY & MAC by setting upper bounds on the delay through each layer which allows higher layers to comprehend the delays & response times to pause frames. Each new speed & PHY in 802.3 is accompanied by delay constraint specifications to support this.

    Q.  Do you have an overlay graphic that shows the Ethernet RDMA roadmap?  If so, is Ethernet storage the primary driver for that technology?

    A.  Beyond the scope of this presentation on Ethernet.  Ethernet is defined by the IEEE for L1 and L2 in the ISO model.  Your questions are at L3 and L4, which is handled by organizations like IETF and the InfiniBand Trade Association.

    Q. The adoption of faster and new Ethernet always has to do with the costs of acquiring new technology. How long do you think it will take to adopt/acquire faster Ethernet in datacenters now that the development is happening much faster than the last 20 years?

    A. Please see the chart on slide 7 where Crehan Research predicts how fast the technology will diffuse into deployments.

    Q. What do you expect as cost comparison between Ethernet and InfiniBand going forward?
    Also, what work is being done to reduce latency?

    A. Beyond the scope of this presentation.  Latency is primarily a consequence of design methodologies and semiconductor process technology, and thus under the control of the silicon device manufacturers.  Some vendors prioritize latency more than others.

    Q. What’s the technical limitation as speeds go higher and higher?

    A. A number of factors limit speeds going faster and faster, but the main problem is that materials attenuate signals as they travel at higher frequencies.

    Q. Will 1GbE used for manageability purposes disappear from public cloud? If so, what is the expected time frame?

    A. This is a choice for end users.  Most equipment is managed on a separate network for security concerns, but users can eliminate these management networks at any time.

    Q. What are the relative market size predictions for the expanding number of standards (25G, 50G, 100G, 200G, etc.)?

    A. See the Crehan Research forecast in the presentation.

    Q. What is the major difference between SMF & MMF for the not so initiated?

    A. The SMF has a 9um core while the MMF has a 50um core.  Different lasers are used for each fiber type and MMF typically goes 100 meters above 10GbE and SMF goes from 500m to 10km.

    Q. Will 25G be available through both copper and fibre connectivity?

    A. Yes.  IEEE 802.3 work is currently underway to specify 25Gb/s on twinax (“direct attach copper)” to 5 meters, printed circuit backplane up to ~1m, twisted pair copper to 30m, multimode fiber to 100m.  There is no technology barrier to 25G on SMF, just that a standards project to specify it has not started yet.

    Q. This is interesting from a hardware viewpoint, but has nothing to do with storage yet.  Are we going to get to how this relates to storage other than saying flash drives are fast and only Ethernet can keep up?

    A. Beyond the scope of this presentation on Ethernet.  Ethernet is defined by the IEEE for L1 and L2 in the ISO model.  Your questions are directed at the higher layers.  The key point of this webcast is that storage networking engineers need to pay much more attention to the Ethernet roadmap than they have historically, primarily because of NVM.

    Q. How does “SFP 28″ fit in this mix?  Is it required for 25G?

    A. SFP28 connectors and modules are required for 25GbE because they give better performance than SFP+ that only works to 10GbE.

    Q. Can you provide the quick difference between copper & optical on speed & costs?

    A. Copper and optical Ethernet links are usually standardized at the same speed.  400GbE is not defining a copper link but an active Direct Attached Cable (DAC) will probably support 400GbE.  Cost depends on volume and many factors and is beyond the scope of this presentation.  Copper is usually a fraction of the cost of optical links.

    Q. Do you think people will try to use multiple CAT 5e to get more aggregate bandwidth to the access points to avoid having to run Fibre to them?

    A. IEEE is defining 2.5GBASE-T and 5GBASE-T to enable Cat5e to support faster wireless access points.

    Q. When are higher speeds and PoE going to reach the point when copper based Ethernet will become a viable heat source for buildings thus helping the environment?

    A. :)  IEEE is defining 4 wire PoE to deliver at least 60W to end devices.  You can find out more here.

    Q. What are the use cases for 2.5Gb and 5.0Gb Base-T?

    A. The leading use case for 2.5G/5GBASE-T is to provide the uplink for wireless LAN access points that support 802.11ac and future wireless technology.  Wireless LAN technology has advanced to the point where >1Gb/s BW is needed upstream from the AP, and 2.5G/5G provide a higher speed uplink while preserving the user’s investment in Cat5e/Cat6 cabling.

    Q. Why not have only CFP2 sockets right away with things disabled for lower speeds for all the intervening years leading to full-fledged CFP2?

    A. CFP2 is defined for 100GbE and 8 ports can be used on a 1U switch. 100GbE switches are shifting to QSFP28 so that 32 ports of 100GbE is supported in a 1U switch at low cost.  The CFP2 is much more expensive than QSFP28 and will not be used for lower speeds because of the high cost.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     


    The Life of a Storage Packet

    July 5th, 2015

    Keeping storage as close to the application as possible and reasonable is important, but different types of storage can make a big difference for performance as well as types of workloads. Starting with the basics and working to more complexity, find out how storage really works in this first of the Packet Walk series of the “Napkin Dialogues” series. Warning: You’re on your own when tipping the pizza delivery person!

    Download (PDF, 1.71MB)