The main features of 2016 Failover Cluster
Posted by Vitalii Feshchenko on February 1, 2018

storage-qos

In our support work very often we face different environments. They can range from three VMs to a hundred of those, with the number of nodes from two to ten.

Today, I will tell you about the main features of Failover Cluster 2016, which are applicable to any environment.

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What’s Split Brain and how to avoid it like the plague?
Posted by Sergey Sanduliak on January 3, 2018

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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3 Generations of My Homelabs
Posted by Askar Kopbayev on August 15, 2017

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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StarWind VVols for VMware vSphere Environment
Posted by Dmytro Malynka on June 16, 2017

VMDK file to LUN storage architecture has been the most usable scenario for years until VMware released Virtual Volumes in vSphere 6.0. In the case of an array with block access, own VMware file system – VMFS  – was used -, and NFS was used for file storage. The array capacity was divided into LUNs or NFS-shares and presented ESXi hosts in the datastore form. Frequently, datastore is a large capacity storage housing numerous VMs. In fact, allocating a separate datastore for each VM is quite inconvenient and time-consuming in terms of administration.

With this approach, the VM storage maintenance operations are at the datastore level, and not at the Virtual Machine level. The operations like snapshots, replication, deduplication, encryption, etc. are performed at the storage level, thus being implemented faster with no use of compute and networking resources. The traditional VM storage technology described in vSphere is still supported. At once, Virtual Volumes (VVols) is an object containing VM files virtual disks and their derivatives.

This handy and at the same time advanced technology was integrated with StarWind Products, that I am about to implement.

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Supermicro SuperServer E200-8D/E300-8D review
Posted by Alex Khorolets on April 21, 2017

These days, more and more companies need high-quality, reliable and efficient server hardware.  Home labs used by enthusiasts and professionals in the IT sphere for software developing and testing, studying for an IT certification, and configuring virtual environments became popular as well. Small companies are also interested in cheap and compact servers, the production of which is based on a couple of virtual machines or networking applications.

Supermicro company ranks one of the leading positions in server development for a long time. Supermicro products range from the Hi-End clusters to microservers. Recently the company released two compact servers: SuperServer E200-8D and its younger model – SuperServer E300-8D.

Supermicro SuperServers

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Design a ROBO infrastructure (Part 3): Infrastructure at remote office side
Posted by Andrea Mauro on March 30, 2017

Design a ROBO scenario must match finally the reality of the customers’ needs, its constraints but also the type of workload and the possible availability solutions of them.

Logical design of a ROBO scenario

When can found the different type of approaches:

  • No server(s) at
  • Few servers (that maybe can fail)
  • Some servers with “relaxed” availability requirements
  • Some servers with reasonable availability

Let’s analyze each of them.

Design a ROBO scenario must match finally the reality of the customers’ needs, its constraints but also the type of workload and the possible availability solutions of them.

Hyper-Converged Infrastructure structure

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vSphere 6.5: HA & DRS improvements. Part 2
Posted by Askar Kopbayev on March 3, 2017

In Part II we will review the remaining improvements in vSphere Availability and Resource Management brought by vSphere 6.5.

Challenge: HA Restart priorities are not flexible enough

Description

Modern applications can be very complex and may consist of more than one server. Very often multi-tier applications require specific restart order, e.g. classic scheme DB – App – Web.  For instance, if an application server powers on before the database server the application will fail to start. To make it worse, there is no guarantee that the application server will automatically recover after DB server is powered on.  Sometimes the application server will have to be rebooted to restore the service. Moreover, there could be inter-application dependencies which make the situation even more complicated.

DRS in vSphere 6.5 view

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vSphere 6.5: HA & DRS improvements. Part I
Posted by Askar Kopbayev on March 2, 2017

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

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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vCenter Server High Availability Review – Part 1
Posted by Askar Kopbayev on November 24, 2016

VCHA overview

High Availability for vCenter Server has never been as important as today when there are so many products dependant on vCenter, e.g. VMware NSX, vSAN, Horizon View, etc.

VMware tried different approaches to bring HA to the vCenter.

There has been vSphere HA for a long time. Although it can protect vCenter Server from hardware failure it doesn’t provide protection on the Guest OS level. So, if Postgres DB in vCenter Server Appliance gets corrupted you would have to restore vCSA from a backup copy or rebuild it from the scratch.

standard topology of VCHA

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