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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Celebrating MinIO

Essentially MinIO is a web server …

I vaguely recalled Anand Babu Periasamy (AB as he is known), the CEO of MinIO saying that when I first met him in 2017. I was fresh “playing around” with MinIO and instantly I fell in love with software technology. Wait a minute. Object storage wasn’t supposed to be so easy. It was not supposed to be that simple to set up and use, but MinIO burst into my storage universe like the birth of the Infinity Stones. There was a eureka moment. And I was attending one of the Storage Field Days in the US shortly after my MinIO discovery in late 2017. What an opportunity!

I could not recall how I made the appointment to meeting MinIO, but I recalled myself taking an Uber to their cosy office on University Avenue in Palo Alto to meet. Through Andy Watson (one of the CTOs then), I was introduced to AB, Garima Kapoor, MinIO’s COO and his wife, Frank Wessels, Zamin (one of the business people who is no longer there) and Ugur Tigli (East Coast CTO) who was on the Polycom. I was awe struck.

Last week, MinIO scored a major Series B round funding of USD103 million. It was delayed by the pandemic because I recalled Garima telling me that the funding was happening in 2020. But I think the delay made it better, because the world now is even more ready for MinIO than ever before.

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A conceptual distributed enterprise HCI with open source software

Cloud computing has changed everything, at least at the infrastructure level. Kubernetes is changing everything as well, at the application level. Enterprises are attracted by tenets of cloud computing and thus, cloud adoption has escalated. But it does not have to be a zero-sum game. Hybrid computing can give enterprises a balanced choice, and they can take advantage of the best of both worlds.

Open Source has changed everything too because organizations now has a choice to balance their costs and expenditures with top enterprise-grade software. The challenge is what can organizations do to put these pieces together using open source software? Integration of open source infrastructure software and applications can be complex and costly.

The next version of HCI

Hyperconverged Infrastructure (HCI) also changed the game. Integration of compute, network and storage became easier, more seamless and less costly when HCI entered the market. Wrapped with a single control plane, the HCI management component can orchestrate VM (virtual machine) resources without much friction. That was HCI 1.0.

But HCI 1.0 was challenged, because several key components of its architecture were based on DAS (direct attached) storage. Scaling storage from a capacity point of view was limited by storage components attached to the HCI architecture. Some storage vendors decided to be creative and created dHCI (disaggregated HCI). If you break down the components one by one, in my opinion, dHCI is just a SAN (storage area network) to HCI. Maybe this should be HCI 1.5.

A new version of an HCI architecture is swimming in as Angelfish

Kubernetes came into the HCI picture in recent years. Without the weights and dependencies of VMs and DAS at the HCI server layer, lightweight containers orchestrated, mostly by, Kubernetes, made distribution of compute easier. From on-premises to cloud and in between, compute resources can easily spun up or down anywhere.

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Is Software Defined right for Storage?

George Herbert Leigh Mallory, mountaineer extraordinaire, was once asked “Why did you want to climb Mount Everest?“, in which he replied “Because it’s there“. That retort demonstrated the indomitable human spirit and probably exemplified best the relationship between the human being’s desire to conquer the physical limits of nature. The software of humanity versus the hardware of the planet Earth.

Juxtaposing, similarities can be said between software and hardware in computer systems, in storage technology per se. In it, there are a few schools of thoughts when it comes to delivering storage services with the notable ones being the storage appliance model and the software-defined storage model.

There are arguments, of course. Some are genuinely partisan but many a times, these arguments come in the form of the flavour of the moment. I have experienced in my past companies touting the storage appliance model very strongly in the beginning, and only to be switching to a “software company” chorus years after that. That was what I meant about the “flavour of the moment”.

Software Defined Storage

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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.

 

Give back or no give

[ Disclosure: I work for iXsystems™ Inc. Views and opinions are my own. ]

If my memory served me right, I recalled the illustrious leader of the Illumos project, Garrett D’Amore ranting about companies, big and small, taking OpenZFS open source codes and projects to incorporate into their own technology but hardly ever giving back to the open source community. That was almost 6 years ago.

My thoughts immediately go back to the days when open source was starting to take off back in the early 2000s. Oracle 9i database had just embraced Linux in a big way, and the book by Eric S. Raymond, “The Cathedral and The Bazaar” was a big hit.

The Cathedral & The Bazaar by Eric S. Raymond

Since then, the blooming days of proprietary software world began to wilt, and over the next twenty plus year, open source software has pretty much taken over the world. Even Microsoft®, the ruthless ruler of the Evil Empire caved in to some of the open source calls. The Microsoft® “I Love Linux” embrace definitely gave the victory feeling of the Rebellion win over the Empire. Open Source won.

Open Source bag of worms

Even with the concerted efforts of the open source communities and projects, there were many situations which have caused frictions and inadvertently, major issues as well. There are several open source projects licenses, and they are not always compatible when different open source projects mesh together for the greater good.

On the storage side of things, 2 “incidents” caught the attention of the masses. For instance, Linus Torvalds, Linux BDFL (Benevolent Dictator for Life) and emperor supremo said “Don’t use ZFS” partly due to the ignorance and incompatibility of Linux GPL (General Public License) and ZFS CDDL (Common Development and Distribution License). That ruffled some feathers amongst the OpenZFS community that Matt Ahrens, the co-creator of the ZFS file system and OpenZFS community leader had to defend OpenZFS from Linus’ comments.

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The instant value of Open Source Storage

[ Full disclosure: I work for iXsystems™ . Opinions and views are mine. ]

TrueNAS Open Storage logo

The story began …

It was 2011. A friend of a friend called me out of the blue. He was rambling about his company’s storage needs. I recalled vividly that he wanted 100TB, and Dell and HP (before HPE) were hopeless doing NAS (network attached storage) in an Apple environment. They assembled a Frankenstein-ish NAS and plastered a price over MYR$100K around it.

In his environment, the Apple workstations were connected to dozens of WD Cloud Book storage (whatever it was called back then), daisy chained via Firewire to each other. I recalled one workstation had 3 WD “books” daisy chained together. They got the exploding storage needs but performance sucked. With every 2nd or 3rd user, access to files were at a snail pace, taking up to more than 2 minutes to open a file sometimes.

At that time, my old colleague at Sun was fervently talking about ZFS and OpenSolaris™. I told him about this opportunity, and so we began. It was him who used the word “crafter”. “We are not building“, he said, “we are crafting“. He was right.

OpenSolaris logo

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