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Manage VM placement in Hyper-V cluster with VMM
Posted by Romain Serre on September 23, 2016
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The placement of the virtual machines in a Hyper-V cluster is an important step to ensure performance and high availability. To make a highly available application, usually a cluster is deployed spread across two or more virtual machines. In case of a Hyper-V node is crashing, the application must keep working.

But the VM placement concerns also its storage and its network. Let’s think about a storage solution where you have several LUNs (or Storage Spaces) according to a service level. Maybe you have a LUN with HDD in RAID 6 and another in RAID 1 with SSD. You don’t want that the VM which requires intensive IO was placed on HDD LUN.

Storage Classification in Virtual Machine Manager

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Don’t Fear but Respect Redirected IO with Shared VHDX
Posted by Didier Van Hoye on August 25, 2016
5/5 (2)

Introduction

When we got Shared VHDX in Windows Server 2012 R2 we were quite pleased as it opened up the road to guest clustering (Failover clustering in virtual machines) without needing to break through the virtualization layer with iSCSI or virtual Fibre Channel (vFC).

First of all, you need to be aware of the limits of using a shared VHDX in Windows Server 2012 R2.

  1. You cannot perform storage live migration
  2. You cannot resize the VHDX online
  3. You cannot do host based backups (i.e. you need to do in guest backups)
  4. No support for checkpoints
  5. No support for Hyper-V Replica

If you cannot live with these, that’s a good indicator this is not for you. But if you can, you should also take care of the potential redirected IO impact that can and will occur. This doesn’t mean it won’t work for you, but you need to know about it, design and build for it and test it realistically for your real life workloads.

active guest cluster node is running on the Hyper-V host

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Is NVMe Really Revolutionary?
Posted by Jon Toigo on August 19, 2016
4/5 (1)

To hear advocates talk about NVMe – a de facto standard created by a group of vendors led by Intel to connect flash memory storage directly to a PCIe bus (that is, without using a SAS/SATA disk controller) – it is the most revolutionary thing that has ever happened in business computing.  While the technology provides a more efficient means to access flash memory, without passing I/O through the buffers, queues and locks associated with a SAS/SATA controller, it can be seen as the latest of a long line of bus extension technologies – and perhaps one that is currently in search of a problem to solve.

I am not against faster I/O processing, of course.  It would be great if the world finally acknowledged that storage has always been the red-headed stepchild of the Von Neumann machine.  Bus speeds and CPU processing speeds have always been capable of driving I/O faster than mechanical storage devices could handle.  That is why engineers used lots of memory – as caches ahead of disk storage or as buffers on disk electronics directly – to help mask or spoof the mismatch of speed.

latency comparison

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ReFS: Log-Structured
Posted by Anton Kolomyeytsev on April 12, 2016
4.75/5 (4)

Here is a part of a series about Microsoft Resilient File System, first introduced in Windows Server 2012. It shows an experiment, conducted by StarWind engineers, dedicated to seeing the ReFS in action. This part is mostly about the FileIntegrity feature in the file system, its theoretical application and practical performance under real virtualization workload. The feature is responsible for data protection in ReFS, basically the reason for “resilient” in its name. It’s goal is avoidance of the common errors that typically lead to data loss. Theoretically, ReFS can detect and correct any data corruption without disturbing the user or disrupting production process.

Device manager

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ReFS: Overview
Posted by Anton Kolomyeytsev on April 9, 2016
4.6/5 (5)

This is a short overview of Microsoft Resilient File System, or ReFS. It introduces the subject and gives a short insight into its main characteristics and theoretical use. It is a part of a series of posts dedicated to ReFS and is, basically, an introduction to the practical posts. All the experiments that show how ReFS really performs, are also listed in the blog. ReFS seems to be a great replacement for the NTFS and its resilience is most convenient for cases, when data loss is critically unacceptable. The file system cooperates with Microsoft Storage Spaces Direct in order to perform automatic corruption repairs, without any attention of the user.

NTFS and ReFS

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Evaluation of Performance and Snapshot Consolidation Process Time in VMware vSphere
Posted by Alex Samoylenko on April 6, 2016
4.5/5 (4)

Snapshots in VMware vSphere often cause various problems with configurations and performance, unless they are properly used – for live backup of virtual machines and temporary keeping VM configuration before the update.

However, using them in large infrastructures is unavoidable. At some point you may need to delete/consolidate virtual machine snapshots (Delete All button in Snapshot Manager), which is quite time-consuming and demanding in terms of storage performance. Thus it would be a good thing to know in advance how much time it takes.

VM snapshot

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