Layers in Storage – For better or worse

Storage arrays and storage services are built upon by layers and layers beneath its architecture. The physical components of hard disk drives and solid states are abstracted into RAID volumes, virtualized into other storage constructs before they are exposed as shares/exports, LUNs or objects to the network.

Everyone in the storage networking industry, is cognizant of the layers and it is the foundation of knowledge and experience. The public cloud storage services side is the same, albeit more opaque. Nevertheless, both have layers.

In the early 2000s, SNIA® Technical Council outlined a blueprint of the SNIA® Shared Storage Model, a framework describing layers and properties of a storage system and its services. It was similar to the OSI 7-layer model for networking. The framework helped many industry professionals and practitioners shaped their understanding and the development of knowledge in their respective fields. The layering scheme of the SNIA® Shared Storage Model is shown below:

SNIA Shared Storage Model – The layering scheme

Storage vendors layering scheme

While SNIA® storage layers were generic and open, each storage vendor had their own proprietary implementation of storage layers. Some of these architectures are simple, but some, I find a bit too complex and convoluted.

Here is an example of the layers of the Automated Volume Management (AVM) architecture of the EMC® Celerra®.

EMC Celerra AVM Layering Scheme

I would often scratch my head about AVM. Disks were grouped into RAID groups, which are LUNs (Logical Unit Numbers). Then they were defined as Celerra® dvols (disk volumes), and stripes of the dvols were consolidated into a storage pool.

From the pool, a piece of a storage capacity construct, called a slice volume, were combined with other slice volumes into a metavolume which eventually was presented as a file system to the network and their respective NAS clients. Explaining this took an effort because I was the IP Storage product manager for EMC® between 2007 – 2009. It was a far cry from the simplicity of NetApp® ONTAP 7 architecture of RAID groups and volumes, and the WAFL® (Write Anywhere File Layout) filesystem.

Another complicated layered framework I often gripe about is Ceph. Here is a look of how the layers of CephFS is constructed.

Ceph Storage Layered Framework

I work with the OpenZFS filesystem a lot. It is something I am rather familiar with, and the layered structure of the ZFS filesystem is essentially simpler.

Storage architecture mixology

Engineers are bizarre when they get too creative. They have a can do attitude that transcends the boundaries of practicality sometimes, and boggles many minds. This is what happens when they have their own mixology ideas.

Recently I spoke to two magnanimous persons who had the idea of providing Ceph iSCSI LUNs to the ZFS filesystem in order to use the simplicity of NAS file sharing capabilities in TrueNAS® CORE. From their own words, Ceph NAS capabilities sucked. I had to draw their whole idea out in a Powerpoint and this is the architecture I got from the conversation.

There are 3 different storage subsystems here just to provide NAS. As if Ceph layers aren’t complicated enough, the iSCSI LUNs from Ceph are presented as Cinder volumes to the KVM hypervisor (or VMware® ESXi) through the Cinder driver. Cinder is the persistent storage volume subsystem of the Openstack® project. The Cinder volumes/hypervisor datastore are virtualized as vdisks to the respective VMs installed with TrueNAS® CORE and OpenZFS filesystem. From the TrueNAS® CORE, shares and exports are provisioned via the SMB and NFS protocols to Windows and Linux respectively.

It works! As I was told, it worked!

A.P.P.A.R.M.S.C. considerations

Continuing from the layered framework described above for NAS, other aspects beside the technical work have to be considered, even when it can work technically.

I often use a set of diligent data storage focal points when considering a good storage design and implementation. This is the A.P.P.A.R.M.S.C. Take for instance Protection as one of the points and snapshot is the technology to use.

Snapshots can be executed at the ZFS level on the TrueNAS® CORE subsystem. Snapshots can be trigged at the volume level in Openstack® subsystem and likewise, rbd snapshots at the Ceph subsystem. The question is, which snapshot at which storage subsystem is the most valuable to the operations and business? Do you run all 3 snapshots? How do you execute them in succession in a scheduled policy?

In terms of performance, can it truly maximize its potential? Can it churn out the best IOPS, and deliver at wire speed? What is the latency we can expect with so many layers from 3 different storage subsystems?

And supporting this said architecture would be a nightmare. Where do you even start the troubleshooting?

Those are just a few considerations and questions to think about when such a layered storage architecture along. IMHO, such a design was over-engineered. I was tempted to say “Just because you can, doesn’t mean you should

Elegance in Simplicity

Einstein (I think) quoted:

Einstein’s quote on simplicity and complexity

I am not saying that having too many layers is wrong. Having a heavily layered architecture works for many storage solutions out there, where they are often masked with a simple and intuitive UI. But in yours truly point of view, as a storage architecture enthusiast and connoisseur, there is beauty and elegance in simple designs.

The purpose here is to promote better understanding of the storage layers, and how they integrate and interact with each other to deliver the data services to the network. In the end, that is how most storage architectures are built.


Storageless shan’t be thy name

Storageless??? What kind of a tech jargon is that???

This latest jargon irked me. Storage vendor NetApp® (through its acquisition of Spot) and Hammerspace, a metadata-driven storage agnostic orchestration technology company, have begun touting the “storageless” tech jargon in hope that it will become an industry buzzword. Once again, the hype cycle jargon junkies are hard at work.

Clear, empty storage containers

Clear, nondescript storage containers

It is obvious that the storageless jargon wants to ride on the hype of serverless computing, an abstraction method of computing resources where the allocation and the consumption of resources are defined by pieces of programmatic code of the running application. The “calling” of the underlying resources are based on the application’s code, and thus, rendering the computing resources invisible, insignificant and not sexy.

My stand

Among the 3 main infrastructure technology – compute, network, storage, storage technology is a bit of a science and a bit of dark magic. It is complex and that is what makes storage technology so beautiful. The constant innovation and technology advancement continue to make storage as a data services platform relentlessly interesting.

Cloud, Kubernetes and many data-as-a-service platforms require strong persistent storage. As defined by NIST Definition of Cloud Computing, the 4 of the 5 tenets – on-demand self-service, resource pooling, rapid elasticity, measured servicedemand storage to be abstracted. Therefore, I am all for abstraction of storage resources from the data services platform.

But the storageless jargon is doing a great disservice. It is not helping. It does not lend its weight glorifying the innovations of storage. In fact, IMHO, it felt like a weighted anchor sinking storage into the deepest depth, invisible, insignificant and not sexy. I am here dutifully to promote and evangelize storage innovations, and I am duly unimpressed with such a jargon.

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A Paean to NFS

It is certainly encouraging to see both NAS protocols, NFS and SMB, featured well in the latest VMware® vSAN 7 Update 1 release. The NFS v3 and v4.1 support was already in vSAN 7.0 when it was earlier announced as part of its Native File Services for vSAN. But some years ago, NFS was not always the primary storage protocol of choice. SAN protocols, Fibre Channel and iSCSI, were almost always designated to serve enterprise applications. At the client side, Windows became prominent, and the SMB/CIFS protocol dominated the landscape of the desktop. This further pushed NFS into the back closet.

NFS or Network File System has its naysayers. The venerable, but often maligned distributed network file protocol is 36 years today. In storage vendors such as NetApp®, VAST Data, Pure Storage FlashBlade, and Dell EMC Isilon, NFS is still positioned as the primary file protocol for manufacturing testers on the shop floor, EDA/eCAD applications, seismic and subsurface applications in Oil & Gas and many more. In another development, just like its presence in the vSAN Native Services,, NFS has also quietly embedded itself into many storage platforms to serve the data platform services within the respective framework itself.

And I have experienced NFS from the client side to the enterprise applications and more, and I take this opportunity to pay tribute.

NFS (Network File System) client server network

NFS (Network File System) client server network

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The prudence needed for storage technology companies

Blitzscaling has been on my mind a lot. Ever since I discovered that word a while back, it has returned time and time again to fill my thoughts. In the wake of COVID-19, and in the mire of this devastating pandemic, is blitzscaling still the right strategy for this generation of storage technology, hyperconverged, data management and cloud storage startups?

What the heck is Blitzscaling? 

For the uninformed, here’s a video of Reid Hoffman, co-founder of Linked and a member of the Paypal mafia, explaining Blitzscaling.

Blitzscaling is about hyper growing, scaling ultra fast and rocketing to escape velocity, at the expense of things like management efficiency, financial prudence, profits and others. While this blog focuses on storage companies, blitzscaling is probably most recognizable in the massive expansion of Uber (and contraction) a few years ago. In the US, the ride hailing war is between Uber and Lyft, but over here in South East Asia, just a few years back, it was between Uber and Grab. In China it was Uber and Didi.

From the storage angle, 2 segments exemplified the blitzscaling culture between 2015 and 2020.

  • All Flash Startups
  • Hyper Converged Infrastructure Startups

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Resilient Integrated Data Protection against Ransomware

Early in the year, I wrote about NAS systems being a high impact target for ransomware. I called NAS a goldmine for ransomware. This is still very true because NAS systems are the workhorses of many organizations. They serve files and folders and from it, the sharing and collaboration of Work.

Another common function for NAS systems is being a target for backups. In small medium organizations, backup software often direct their backups to a network drive in the network. Even for larger enterprise customers too, NAS is the common destination for backups.

Backup to NAS system

Typical NAS backup for small medium organizations.

Backup to Data Domain with NAS Protocols

Backup to Data Domain with NAS (NFS, CIFS) Protocols

Ransomware is obviously targeting the backup as another high impact target, with the potential to disrupt the rescue and the restoration of the work files and folders.

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Down the rabbit hole with Kubernetes Storage

Kubernetes is on fire. Last week VMware® released the State of Kubernetes 2020 report which surveyed companies with 1,000 employees and above. Results were not surprising as the adoptions of this nascent technology are booming. But persistent storage remained the nagging concern for the Kubernetes serving the infrastructure resources to applications instances running in the containers of a pod in a cluster.

The standardization of storage resources have settled with CSI (Container Storage Interface). Storage vendors have almost, kind of, sort of agreed that the API objects such as PersistentVolumes, PersistentVolumeClaims, StorageClasses, along with the parameters would be the way to request the storage resources from the Pre-provisioned Volumes via the CSI driver plug-in. There are already more than 50 vendor specific CSI drivers in Github.

Kubernetes and CSI initiative

Kubernetes and the CSI (Container Storage Interface) logos

The CSI plug-in method is the only way for Kubernetes to scale and keep its dynamic, loadable storage resource integration with external 3rd party vendors, all clamouring to grab a piece of this burgeoning demands both in the cloud and in the enterprise.

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Rebooting Infrascale

[ Disclosure: I was invited by GestaltIT as a delegate to their Storage Field Day 19 event from Jan 22-24, 2020 in the Silicon Valley USA. My expenses, travel, accommodation and conference fees were covered by GestaltIT, the organizer and I was not obligated to blog or promote the vendors’ technologies to be presented at this event. The content of this blog is of my own opinions and views ]

Infrascale™ was relatively unknown for the Storage Field Day 19 delegates when they presented a few weeks ago in San Jose. Between 2015-2017, they have received several awards and accolades, including being in the Leaders quadrant for the 2017 Gartner Magic Quadrant for DR-as-a-Service.

I have known of Infrascale since 2016 as the BC and DR landscape was taking off back then, gravitating towards the cloud as a secondary platform for recovery.

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Green Storage? Meh!

Something triggered my thoughts a few days ago. A few of us got together talking about climate change and a friend asked how green was the datacenter in IT. With cloud computing booming, I would say that green computing isn’t really the hottest thing at present. That in turn, leads us to one of the most voracious energy beasts in the datacenter, storage. Where is green storage in the equation?

What is green?

Over the past decade, several storage related technologies were touted as more energy efficient. These include

  • Tape – when tapes are offline, they do not consume power and do not require cooling
  • Virtualization – Virtualization reduces the number of servers and desktops, and of course storage too
  • MAID (Massive Array of Independent Disks) – the arrays spin down the HDDs if idle for a period of time
  • SSD (Solid State Drives) – Compared to HDDs, SSDs consume much less power, and overall reduce the cooling needs
  • Data Footprint Reduction – Deduplication, compression and other technologies to reduce copies of data
  • SMR (Shingled Magnetic Recording) Drives – Higher areal density means less drives but limited by physics.

The largest gorilla in storage technology

HDDs still dominate the market and they are the biggest producers of heat and vibration in a storage array, along with the redundant power supplies and fans. Until and unless SSDs dominate, we have to live with the fact that storage disk drives are not green. The statistics from Statistica below forecasts that in 2021, the shipment of SSDs will surpass HDDs.

Today the areal density of HDDs have increased. With SMR (shingled magnetic recording), the areal density jumped about 25% more than the 1Tb/inch (Terabit per inch) in the CMR (conventional magnetic recording) drives. The largest SMR in the market today is 16TB from Seagate with 18TB SMR in the horizon. That capacity is going to grow significantly when EAMR (energy assisted magnetic recording) – which counts heat assisted and microwave assisted – drives enter the market next year. The areal density will grow to 1.6Tb/inch with a roadmap to 4.0Tb/inch. Continue reading

Brainy Commvault

[Disclosure: I was invited by Commvault as a Media person and Social Ambassador to their Commvault GO 2019 Conference and also a Tech Field Day eXtra delegate from Oct 13-17, 2019 in the Denver CO, USA. My expenses, travel, accommodation and conference fees were covered by Commvault, the organizer and I was not obligated to blog or promote their technologies presented at this event. The content of this blog is of my own opinions and views]

The waltz across the Commvault-Hedvig mine field will not be easy. Commvault will have a lot of open discussions about their acquisition of Hedvig and how Hedvig “primary storage platform” will fit into a “secondary storage framework” of Commvault. The outcome of this consummation is yet to appear as a structured form. The storyline will eventually form as Commvault’s diligence to define their strategy moving forward.

Day 1

Day 1 was my open day at Commvault GO. I was absorbing the first impressions of Commvault again even though this was my third Commvault GO, after Washington DC and Nashville in 2017 and 2018 respectively. There was certainly a “startup” feeling again in Commvault since the appointment of Sanjay Mirchandani as CEO 9 months ago.

A lot of excitement and buzz were generated around the metallic, the Commvault venture into Software-as-a-Service (SaaS). The SaaS solution is targeted at the mid-market for organizations with 500-2500 staff count. Its simplicity and pricing were the 2 things which gave me a good feeling all over. There is even a 45-day trial for metallic.

Getting Brainy

My Day 2 itinerary was more specific because my agenda for this trip was to seek answers to the realization of Commvault-Hedvig.

Commvault took the distinction of using the vision of a DataBrain (#databrain) to define their strategy. From the picture below, the left and right hemisphere of the DataBrain forms the Storage Management piece on the left and Data Management on the right.

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