Why upgrade to VMware vSphere 6.5 (or why not)
Posted by Andrea Mauro on January 31, 2018
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VMware vSphere 6.5 is the latest version of the enterprise server virtual platform from VMware, but the new beta it’s already there for testers. Actually the next version it’s (in the beta). If you are building a new infrastructure from scratch the latest stable version is probably the best choices (for most cases); but what about if you have an old environment and you plan to upgrade it?

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What’s Split Brain and how to avoid it like the plague?
Posted by Sergey Sanduliak on January 3, 2018
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In this article, we will discuss the split brain issue, and different approaches to prevent it from happening.

The situation when communication loss between the cluster nodes is caused by network connection problems is called network partition, which can lead to split brain. According to Wikipedia, split brain is a computer term, based on an analogy with the medical split-brain syndrome. It can be a real horror for a system administrator to handle the consequences of a split brain.

A split brain can happen if active nodes lose all synchronization and heartbeat connections between them at the same time and are not able to communicate anymore to define the synchronization state of the partner node. Split brain indicates data or availability inconsistencies originating from the maintenance of two separate data sets with overlap in scope.

split brain syndrome

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High-performing and highly available Scale-Out File Server with SMB3
Posted by Ivan Talaichuk on December 6, 2017
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There’s, probably, no IT administrator who hasn’t heard of SMB3 (Server Message Block). is an application-layer network protocol, developed by Microsoft mostly to provide shared access to the files, and allowing communication between nodes. SMB has been designed as a tool for the creation of a DOS-based network file system, but Microsoft took the initiative and renamed SMB into CIFS later on (Common Internet File System) and continued further developing it. The second version – SMB 2.0, has been introduced in Windows Vista with a wide range of new features, thus it became clear that Microsoft was working hard to improve this protocol.

Now, to SMB3. It’s an improved version of the previous Server Message Block protocol that Microsoft introduced as one of the key features in Windows Server 2012 operating system. SMB3 comes with a significant number of new capabilities like SMB Transparent Failover, SMB Encryption, VSS for SMB file shares, SMB Direct (SMB over RDMA) and SMB Multichannel. SMB Multichannel allows file servers to use multiple network connections simultaneously, therefore increasing performance and adding one more level of Fault Tolerance within the networking layer.

Failover Cluster Manager with SOFS roles

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3 Generations of My Homelabs
Posted by Askar Kopbayev on August 15, 2017
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Sooner or later every single IT guy comes to the idea of having some lab. There are a million reasons why you would need a lab: learning new technologies, improving skills, trying crazy ideas you would never dare to try in the production network, you name it. Even though it is a work-related activity for most home labbers this is just another hobby for many of us.  That’s why people spend so many hours of their personal time building the homelab, investing significant funds into new hardware, thoroughly planning its setup, looking for a help in online communities or sharing their experience to help others. There is a whole universe of home labbers and I am happy to be part of this community.

In this post, I would like to share my experience with 3 generations of home labs I have had so far and the thoughts about next generation.

high-level network diagram

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Disaster Recovery and why hypervisor HA may not be best
Posted by Gary Williams on August 10, 2017
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A lot of the time I see and speak to people asking about DR solutions when what they really want is HA with a few backups so I wanted to use a blog article to go through some of the technical terms used in conjunction with DR.

When people say “I want DR”, I’ll ask them about the sort of disasters they are looking to protect against and most of the time the response is “I want to keep working if my hypervisor crashes”.

Linux VMs restart

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Design a ROBO infrastructure. Part 4: HCI solutions
Posted by Andrea Mauro on June 7, 2017
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2-nodes hyperconverged solution

As written in the previous post, for ROBO scenario the most interesting HCI (Hyper-Converged Infrastructure) configuration is a two nodes configuration, considering that two nodes could be enough to run dozen VMs (or also more).

For this reason, not all hyperconverged solutions could be suitable for this case (for example Nutanix or Simplivity need at least 3 nodes). And is not simple scale down an enterprise solution to a small size, due to the architecture constraints.

Actually, there are some interesting products specific for HCI in ROBO scenario:

  • VMware Virtual SAN in a 2 nodes clusters
  • StarWind Virtual Storage Appliance
  • StorMagic SvSAN

StarWind Virtual SAN overall architecture

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vSphere 6.5: HA & DRS improvements. Part I
Posted by Askar Kopbayev on March 2, 2017
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A number of improvements that have been introduced in vSphere HA and DRS in the last several years are impressive. vSphere 6.5 continues this tradition by bringing new features into HA Admission Control, by adding flexibility with HA Orchestrated Restart and by enabling DRS to make more intelligent balancing.

I will be trying a new format today. First, I will be explaining the challenges you might have had in previous vSphere releases and then I will show you how the new vSphere 6.5 HA & DRS features address those challenges.

vSphere admission control cluster resource percentage

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Design a ROBO infrastructure (Part 2): Design areas and technologies
Posted by Andrea Mauro on February 24, 2017
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In the previous post, we have explained and described business requirements and constraints in order to support design and implementation decisions suited for mission-critical applications, considering also how risk can affect design decisions.

Now we will match the following technology aspects to satisfy design requirements:

  • Availability
  • Manageability
  • Performance and scaling
  • Recoverability
  • Security
  • Risk and budget management

ROBO Design areas and technologies

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Storage HA on the Cheap: Fixing Synology DiskStation flaky Performance with StarWind Free. Part 1 (Architecture)
Posted by Vladislav Karaiev on January 4, 2017
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Introduction

DiskStation DS916+ is a further improvement of DS415+ model. Storage capacity in DS916+ can be scaled using DX513 expansion units, making a total of nine 3.5 disk bays. Given the relatively small form factor and impressive capacity potential, such configuration may become a great solution for small businesses and enthusiasts.

Synology DS916+ StarWind

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vCenter Server High Availability Review – Part 2
Posted by Askar Kopbayev on November 25, 2016
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In this second part of VCHA review I will be covering some ‘gotchas’ and configuration steps that are not covered in the VMware availability guide We will also go through all steps of Advanced Configuration.

Managment cluster

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