Enhancing NAS client resiliency and performance with SMB Multichannel and NFS nconnect

NAS (network attached storage) is obviously the file-level workhorse for shared resources in the network of any organization. SMB (server message block) for Windows environments and NFS (network file system) for Linux platforms are the 2 most prominent protocols that rule the NAS world. Of course we have SMB implementations in the form of Samba and others in non-Windows, Linux and NFS implementations in Windows as well.

As the versions of both network file sharing protocols iterated, present versions of SMB v3.x and NFS v4.x (NFS v3 on the supported Linux kernel version) on the client-side have evolved well. Both now have enhanced resiliency and performance improvement features. And there is an underlying similarity of both implementations. This blog looks at the client-side architectures of both.

One TCP connection

NAS is a client-server architecture. Over the network, NAS clients (SMB or NFS) access their corresponding NAS server(s) – SMB or NFS server(s) – through the TCP/IP network.

NAS client-server architecture (Credit: https://hypertecsp.com/en-CA/knowledge-base/nas-vs-san/)

One very important key starting point to note is the use of one TCP connection per NAS client to the NAS server relationship. For both SMB and NFS, there is just one TCP link between client and the server even if there are several SMB mapped shares or NFS mount points respectively on the clients.

For a long time, this one TCP connection is sufficient for the NAS traffic. But as the network file accesses grow, this connection becomes both a single point of failure as well as a performance bottleneck.

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OpenZFS dRAID has risen!

We await the 3rd iteration of TrueNAS® SCALE 23.10 codenamed Cobia. 23.10 means October 2023, and we are within weeks of its announcement.

One of the best features I have been waiting for is dRAID or distributed RAID. I have written about it dRAID a couple of years back. It was announced in 2021, in OpenZFS 2.1, but we have not seen an commercial implementation of dRAID … until iXsystems™ TrueNAS® SCALE 23.10. Why am I so excited?

I have followed the technology since Isaac Huang presented dRAID at the OpenZFS Summit in 2015. Through the years ahead, I have seen Isaac presenting dRAID at the summits, and with each iteration, dRAID got closer and closer to be developed into OpenZFS. It was not until 2021, in OpenZFS 2.1 when dRAID became part of filesystem. And now, dRAID is finally in the TrueNAS® SCALE offering.

Knowing RAID resilvering

RAID rebuilding or reconstruction is a painful and potentially risky process. In OpenZFS and ZFS speak, this process is called resilvering. In simple laymen terms, when a drive (or drives) failed in a parity-based RAID volume (eg. RAID-Z1 or RAID-Z2 vdev), the data which was previously in the failed drive is recreated in the newly integrated spare drive. The structural integrity of the RAID volume (and the storage pool) is preserved but the data that was lost is painstakingly remade through the mathematical algorithm of the parity function of the RAID volume.

When hard disk drives were small in capacity like 2TB or less, the RAID resilvering process was probably faster to complete, returning the parity RAID volume to a normal, online state. But today, drives are 22TB and higher, leaving the traditional RAID resilvering process to take days and even weeks. This leads the RAID volume vulnerable to another possible drive failure, weakening the integrity of the RAID volume. Even worse, most of modern day storage arrays have many disk drives, into the thousands even. And yes, solid state drives would probably be faster in the resilvering, but the same mechanics pretty much apply in OpenZFS.

At the same time, the spare drives are assigned physically and designated to the OpenZFS storage pool, and are not part of the vdev until the resilvering process kicks in.

Yes, this is pretty much a physical process that takes time, computing resources and patience. Note the operative word of “physical” here.

dRAID resilvering

dRAID speeds up the RAID resilvering process several folds, returning the RAID volume (or vdev) much faster than traditional OpenZFS RAID resilvering process. It uses a logical (as opposed to physical) RAID layout concept and uses “logical spare drives”. Thus, there will be many spares “blocks” distributed across the entire dRAID zpool, as shown in the diagram below.

Traditional RAID vdev vs dRAID vdev

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Disaggregation and Composability vital for AI/DL models to scale

New generations of applications and workloads like AI/DL (Artificial Intelligence/Deep Learning), and HPC (High Performance Computing) are breaking the seams of entrenched storage infrastructure models and frameworks. We cannot continue to scale-up or scale-out the storage infrastructure to meet these inundating fluctuating I/O demands. It is time to look at another storage architecture type of infrastructure technology – Composable Infrastructure Architecture.

Infrastructure is changing. The previous staid infrastructure architecture parts of compute, network and storage have long been thrown of the window, precipitated by the rise of x86 server virtualization almost 20 years now. It triggered a tsunami of virtualizing everything, including storage virtualization, which eventually found a more current nomenclature – Software Defined Storage. Both storage virtualization and software defined storage (SDS) are similar and yet different and should be revered through different contexts and similar goals. This Tech Target article laid out both nicely.

As virtualization raged on, converged infrastructure (CI) which evolved into hyperconverged infrastructure (HCI) went fever pitch for a while. Companies like Maxta, Pivot3, Atlantis, are pretty much gone, with HPE® Simplivity and Cisco® Hyperflex occasionally blipped in my radar. In a market that matured very fast, HCI is now dominated by Nutanix™ and VMware®, with smaller Microsoft®, Dell EMC® following them.

From HCI, the attention of virtualization has shifted something more granular, more scalable in containerization. Despite a degree of complexity, containerization is taking agility and scalability to the next level. Kubernetes, Dockers are now mainstay nomenclature of infrastructure engineers and DevOps. So what is driving composable infrastructure? Have we reached the end of virtualization? Not really.

Evolution of infrastructure. Source: IDC

It is just that one part of the infrastructure landscape is changing. This new generation of AI/ML workloads are flipping the coin to the other side of virtualization. As we see the diagram above, IDC brought this mindset change to get us to Think Composability, the next phase of Infrastructure.

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Stating the case for a Storage Appliance approach

I was in Indonesia last week to meet with iXsystems™‘ partner PT Maha Data Solusi. I had the wonderful opportunity to meet with many people there and one interesting and often-replayed question arose. Why aren’t iX doing software-defined-storage (SDS)? It was a very obvious and deliberate question.

After all, iX is already providing the free use of the open source TrueNAS® CORE software that runs on many x86 systems as an SDS solution and yet commercially, iX sell the TrueNAS® storage appliances.

This argument between a storage appliance model and a storage storage only model has been debated for more than a decade, and it does come into my conversations on and off. I finally want to address this here, with my own views and opinions. And I want to inform that I am open to both models, because as a storage consultant, both have their pros and cons, advantages and disadvantages. Up front I gravitate to the storage appliance model, and here’s why.

My story of the storage appliance begins …

Back in the 90s, most of my work was on Fibre Channel and NFS. iSCSI has not existed yet (iSCSI was ratified in 2003). It was almost exclusively on the Sun Microsystems® enterprise storage with Sun’s software resell of the Veritas® software suite that included the Sun Volume Manager (VxVM), Veritas® Filesystem (VxFS), Veritas® Replication (VxVR) and Veritas® Cluster Server (VCS). I didn’t do much Veritas® NetBackup (NBU) although I was trained at Veritas® in Boston in July 1997 (I remembered that 2 weeks’ trip fondly). It was just over 2 months after Veritas® acquired OpenVision. Backup Plus was the NetBackup.

Between 1998-1999, I spent a lot of time working Sun NFS servers. The prevalent networking speed at that time was 100Mbits/sec. And I remember having this argument with a Sun partner engineer by the name of Wong Teck Seng. Teck Seng was an inquisitive fella (still is) and he was raving about this purpose-built NFS server he knew about and he shared his experience with me. I detracted him, brushing aside his always-on tech orgasm, and did not find great things about a NAS storage appliance. Auspex™ was big then, and I knew of them.

I joined NetApp® as Malaysia’s employee #2. It was an odd few months working with a storage appliance but after a couple of months, I started to understand and appreciate the philosophy. The storage Appliance Model made sense to me, even through these days.

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As Disk Drive capacity gets larger (and larger), the resilient Filesystem matters

I just got home from the wonderful iXsystems™ Sales Summit in Knoxville, Tennessee. The key highlight was to christian the opening of iXsystems™ Maryville facility, the key operations center that will house iX engineering, support and part of marketing as well. News of this can be found here.

iX datacenter in the new Maryville facility

Western Digital® has always been a big advocate of iX, and at the Summit, they shared their hard disk drives HDD, solid state drives SSD, and other storage platforms roadmaps. I felt like a kid a candy store because I love all these excitements in the disk drive industry. Who says HDDs are going to be usurped by SSDs?

Several other disk drive manufacturers, including Western Digital®, have announced larger capacity drives. Here are some news of each vendor in recent months

Other than the AFR (annualized failure rates) numbers published by Backblaze every quarter, the Capacity factor has always been a measurement of high interest in the storage industry.

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Building Trust in the Storage Brand

Trust is everything. When done right, the brand is trust.

One Wikibon article last month “Does Hardware (still) Matter?” touched on my sentiments and hit close to the heart. As the world becomes more and more data driven and cloud-centric, the prominence of IT infrastructure has diminished from the purview of the boardroom. The importance of IT infrastructure cannot be discounted but in this new age, storage infrastructure has become invisible.

In the seas of both on-premises and hybrid storage technology solutions, everyone is trying to stand out, trying to eke the minutest ounces of differentiation and advantage to gain the customer’s micro-attention. With all the drum beatings, the loyalty of the customer can switch in an instance unless we build trust.

I ponder a few storage industry variables that help build trust.

Open source Communities and tribes

During the hey-days of proprietary software and OSes, protectionism was key to guarding the differentiations and the advantages. Licenses were common, and some were paired with the hardware hostid to create that “power combination”. And who can forget those serial dongles license keys? Urgh!!

Since the open source movement (Read The Cathedral and the Bazaar publication) began, the IT world has begun to trust software and OSes more and more. Open Source communities grew and technology tribes were formed in all types of niches, including storage software. Trust grew because the population of the communities kept the vendors honest. Gone are the days of the Evil Empire. Even Microsoft® became a ‘cool kid’.


One open source storage filesystem I worked extensively on is OpenZFS. From its beginnings after Open Solaris® (remember build 134), becoming part of the Illumos project and then later in FreeBSD® and Linux upstream. Trust in OpenZFS was developed over time because of the open source model. It has spawned many storage projects including FreeNAS™ which later became TrueNAS®.

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I built a 6-node Gluster cluster with TrueNAS SCALE

I haven’t had hands-on with Gluster for over a decade. My last blog about Gluster was in 2011, right after I did a proof-of-concept for the now defunct, Jaring, Malaysia’s first ISP (Internet Service Provider). But I followed Gluster’s development on and off, until I found out that Gluster was a feature in then upcoming TrueNAS® SCALE. That was almost 2 years ago, just before I accepted to offer to join iXsystems™, my present employer.

The eagerness to test drive Gluster (again) on TrueNAS® SCALE has always been there but I waited for SCALE to become GA. GA finally came on February 22, 2022. My plans for the test rig was laid out, and in the past few weeks, I have been diligently re-learning and putting up the scope to built a 6-node Gluster clustered storage with TrueNAS® SCALE VMs on Virtualbox®.

Gluster on OpenZFS with TrueNAS SCALE

Before we continue, I must warn that this is not pretty. I have limited computing resources in my homelab, but Gluster worked beautifully once I ironed out the inefficiencies. Secondly, this is not a performance test as well, for obvious reasons. So, this is the annals along with the trials and tribulations of my 6-node Gluster cluster test rig on TrueNAS® SCALE.

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Exploring the venerable NFS Ganesha

As TrueNAS® SCALE approaches its General Availability date in less than 10 days time, one of the technology pieces I am extremely excited about in TrueNAS® SCALE is the NFS Ganesha server. It is still early days to see the full prowess of NFS Ganesha in TrueNAS® SCALE, but the potential of Ganesha’s capabilities in iXsystems™ new scale-out storage technology is very, very promising.

NFS Ganesha

I love Network File System (NFS). It was one of the main reasons I was so attracted to Sun Microsystems® SunOS in the first place. 6 months before I graduated, I took a Unix systems programming course in C in the university. The labs were on Sun 3/60 workstations. Coming from a background of a VAX/VMS system administrator in the school’s lab, Unix became a revelation for me. It completely (and blissfully) opened my eyes to open technology, and NFS was the main catalyst. Till this day, my devotion to Unix remained sacrosanct because of the NFS spark aeons ago.

I don’t know NFS Ganesha. I knew of its existence for almost a decade, but I have never used it. Most of the NFS daemons/servers I worked with were kernel NFS, and these included NFS services in Sun SunOS/Solaris, several Linux flavours – Red Hat®, SuSE®, Ubuntu, BSD variants in FreeBSD and MacOS, the older Unices of the 90s – HP-UX, Ultrix, AIX and Irix along with SCO Unix and Microsoft® XenixNetApp® ONTAP™, EMC® Isilon (very briefly), Hitachi® HNAS (née BlueArc) and of course, in these past 5-6 years FreeNAS®/TrueNAS™.

So, as TrueNAS® SCALE beckons, I took to this weekend to learn a bit about NFS Ganesha. Here are what I have learned.

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