Windows SMB synchronous writes with OpenZFS

Sometimes I get really pissed off with myself because I have taken a bigoted view, and ended up with eggs on my face. The past week was like that, and the problem was gnawing me on the inside all week, because I was determined to balance my equilibrium by finding the answer.

Early in the week, I was having a conversation with a potential customer. It evolved around the missing 10 seconds or so of the video footage between the users of a popular video editing software. The company had 70% Windows users, and 30% users on the Mac, both sides accessing the NAS device. The issue was the editors on the Windows side will store the raw and edited files to the NAS, but when the Mac users read them, they will often find 10 seconds or so of the stored video files missing.

The likeliest culprit of this problem is the way the SMB protocol write I/O behaves in Windows and in MacOS. Windows SMB, by default, writes I/O asynchronously while SMB on MacOS writes I/O synchronously.

I had a strong conviction I had the answer to this issue but this was not a TrueNAS®, It was another brand of NAS that I did not have knowledge of, and so, I left the conversation feeling quite embarrassed because I had the answer only on the TrueNAS® server side, not on the Windows client side. Bigotry blinded me. Hmmph! 

SMB (Server Message Block) client-server model

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Setting up Nextcloud on FreeNAS Part 2

[ Note: ] This is a continuation of Setting up Nextcloud on FreeNAS Part 1 in June 2021 blog.

Nextcloud logo

I mentioned in my previous blog that what I did here was not unique. There were many great open source crafters who have done this better than I did. I stood on the shoulders of giants whose videos have helped me to learn and configure Nextcloud on FreeNAS™ (not TrueNAS® CORE, because my weekend exercises were on version 11.2U5). The videos made by Nhan P. Nguyen were instrumental in getting my Nextcloud to work, and I would shamefully admit that I have copied his work almost verbatim.

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Enterprise Storage is not just a Label

I have many anecdotes around the topic of Enterprise Storage, but the conversations in the past 2 weeks made it important for me to share this.

Enterprise Storage is …

Amusing, painful, angry

I get riled up whenever people do not want to be educated about Enterprise Storage. Here are a few that happened in the last 2 weeks.

[ Story #1 ]

A guy was building his own storage for cryptocurrency. He was informed by his supplier that the RAID card was enterprise, and he could get the best performance using “Enterprise” RAID-0.

  • Well, “Enterprise” RAID-0 volume crashed, and he lost all data. Painfully, he said he lost a hefty sum financially

[ Story #2 ]

A media company complained about the reliability of previous storage vendor. The GM was shopping around and was told that there are “Enterprise” SATA drives and the reliability is as good, if not better than SAS drives.

  • The company wanted a fully reliable Enterprise Storage system with 99.999% availability, and yet the SATA interface was not meant to build a more highly reliable enterprise storage. The GM insisted to use “Enterprise” SATA drives for his “enterprise” storage system instead of SAS.  

[ Story #3 ]

An IT admin of a manufacturing company claimed that they had an “Enterprise Storage” system for a few years, and could not figure out why his hard disk drives would die every 12-15 months.

  • He figured out that the drives supplied by his vendor were consumer SATA drives, even though he was told it was an “Enterprise Storage” system when he bought the system.

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First looks into Interplanetary File System

The cryptocurrency craze has elevated another strong candidate in recent months. Filecoin, is leading the voice of a decentralized Internet, the next generation Web 3.0. In this blog, I am not going to write much about the Filecoin frenzy but the underlying distributed file system that powers this phenomenon – The Interplanetary File System.

[ Note: This is still a very new area for me, and the rest of the content of this blog is still nascent and developing ]

Interplanetary File System

Tremulous Client-Server web architecture

The entire Internet architecture is almost client and server. Your clients like browsers, apps, connect to Web services served from a collection of servers. As Web 3.0 approaches (some say it is already here), the client-server model is no longer perceived as the Internet architecture of choice. Billions, and billions of users, applications, devices relying solely on a centralized service would lead to many impactful consequences, and the reasons for decentralization, away from the client-server architecture models of the Internet are cogent.

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Setting up Nextcloud on FreeNAS Part 1

I have started to enhance the work that I did last weekend with Nextcloud on FreeNAS™. I promised to share the innards of my work but first I have to set the right expectations for the readers. This blog is just a documentation of the early work I have been doing to get Nextcloud on FreeNAS™ off the ground quickly. Also there are far better blogs than mine on the Nextcloud topic.


Nextcloud 17 (latest version is version 21)

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My 2-day weekend with Nextcloud on FreeNAS

In recent weeks, I have been asked by friends and old cust0mers on how to extend their NAS shared drives to work-from-home, the new reality. Malaysia went into a full lockdown as of June 1st several days ago.

I have written about file synchronization stories before but I have never done a Nextcloud blog. I have little experience with TrueNAS® CORE Nextcloud plugin and this was a good weekend to build it up from scratch with Virtualbox with FreeNAS™ 11.2U5 (because my friend was using that version).

[ Note ] FreeNAS™ 11.2U5 has been EOLed.

Nextcloud login screen

So, here it how it went for my little experiment. FYI, this is not a How-to guide. That will come later after I have put all my notes together with screenshots and all. This is just a collection of my thoughts while setting up Nextcloud on FreeNAS™.

Dropbox® is expensive

Using cloud storage with file sync and share capability is not exactly a cheap thing especially when you are a small medium sized business or a school or a charity organization. Here is the pricing table for Dropbox® for Business :

Dropbox for business pricing

I am using Dropbox® as the example here but the same can be said for OneDrive or Google Drive and others. The pricing can quickly add up when the price is calculated per user per month.

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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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The hot cold times of HCI

Hyperconverged Infrastructure (HCI) is a hot technology. It has been for the past decade since Nutanix™ took the first mover advantage from the Converged Infrastructure (CI) technology segment and made it pretty much its ownfor a while.

Hyper Converged Infrastructure

But the HCI market (not the technology) is a strange one. It is hot. It is cold. The perennial leader, Nutanix™, has yet to eke out a profitable year. VMware® is strong in the market. Cisco™, which was hot with their HyperFlex solution in 2019, was also stopped short with a dismal decline in the IDC Worldwide HCI 2Q2020 tracker below:

IDC Worldwide Hyperconverged Infrastructure Tracker – 2Q2020

dHCI = Disaggregated or discombobulated? 

dHCI is known as disaggregated HCI. The disaggregation part is disaggregated hardware, especially on the storage part. Vendors like HPE® with Nimble Storage, Hitachi Vantara, NetApp® and a few more have touted the disaggregation of the performance and capacity, the separation of storage and compute as a value proposition but through close inspection, it is just another marketing ploy to attach a SAN storage to servers. It was marketing old wine in a new bottle. As rightly pointed out by my friend, Charles Chow of Commvault® quoted in his blog

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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.


Fueling the Flywheel of AWS Storage

It was bound to happen. It happened. AWS Storage is the Number 1 Storage Company.

The tell tale signs were there when Silicon Angle reported that AWS Storage revenue was around USD$6.5-7.0 billion last year and will reach USD$10 billion at the end of 2021. That news was just a month ago. Last week, IT Brand Pulse went a step further declaring AWS Storage the Number 1 in terms of revenue. Both have the numbers to back it up.

AWS Logo

How did it become that way? How did AWS Storage became numero uno?

Flywheel juggernaut

I became interested in the Flywheel concept some years back. It was conceived in Jim Collins’ book, “Good to Great” almost 20 years ago, and since then, has become the real life enactment of the Flywheel concept. Flywheel – How each turn becomes sturdier, brawnier.

Every turn of the flywheel requires the same amount of effort although in the beginning, the noticeable effect is minuscule. But as every turn gains momentum, the returns of each turn scales greater and greater to the fixed efforts of operating a single turn.

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