Yellow Bricks

by Duncan Epping

esxi

Mythbusters: Hyperthreading and VMware FT

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When vSphere was still in beta one of the requirements for using FT was to have hyperthreading disabled. For most people this wasn’t an issue as traditional hyperthreading usually did not improve performance and thus was disabled by default. However with the Nehalem all this changed. Of course I can’t guarantee a specific percentage of performance increase but increases of up to 20% have been reported which is the primary reason for having HT enabled on any Nehalem system.

As you can imagine the HT requirement for FT has been floating around ever since and is a myth which have never been debunked. I’ve spoken with product management about it and they confirmed it’s an obsolete requirement. Hyperthreading does not have to be disabled for FT to work. Or to put it even more strongly: FT is supported on systems which have hyperthreading enabled. Product Management promised me that a KB article will be created to debunk this myth or an entry will be added to the FT FAQ KB article soon.

UPDATE: The FT FAQ KB Article has been updated and includes the following statement.

Does Fault Tolerance support Intel Hyper-Threading Technology?
Yes, Fault Tolerance does support Intel Hyper-Technology on systems that have it enabled. Enabling or disabling Hyper-Threading has no impact on Fault Tolerance.

Understanding Memory Resource Management in VMware ESX Server

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VMware white-papers are my primary source of information. Almost every single one of them contains valuable information. VMware  just released a brand new white paper titled “Understanding Memory Resource Management in VMware ESX Server” which is most definitely worth reading.

Download:
http://www.vmware.com/files/pdf/perf-vsphere-memory_management.pdf

Description: VMware® ESX™ is a hypervisor designed to efficiently manage hardware resources including CPU, memory, storage, and network among
multiple concurrent virtual machines. This paper describes the basic memory management concepts in ESX, the configuration
options available, and provides results to show the performance impact of these options.

VMware Studio 2.0 GA’ed

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A couple of weeks ago I wrote about VMware Studio 2.0. VMware Studio 2.0 has just officially been released.

Source:
VMware Studio 2.0 helps author, configure, deploy and customize vApps and virtual appliances. vApps support the industry standard Open Virtualization Format (OVF). vApps can be deployed on VMware vSphere 4.0 or in the cloud. vCenter Server 4.0 now supports creating and running vApps, as well as importing and exporting them in compliance with OVF 1.0 standard.

Studio 2.0 is designed to be used by ISVs, developers, IT professionals and members of the virtualization community. It is a free product and is available as a virtual appliance.

The following new features have been added:

  • Ability to create multiple-VM appliances, or vApps, to run on VMware vSphere.
  • More provisioning engines including ESX/ESXi 3.5 and 4, VMware Workstation 6.5.1, and VMware Server 2.0.
  • Build support for Windows Server 2003 and 2008 (32-bit and 64-bit) virtual appliances.
  • Build support for 64-bit Red Hat Enterprise Linux (RHEL) and SUSE Enterprise Linux Server (SLES).
  • Build support new Linux distributions RHEL 5.3, CentOS 5.3, and Ubuntu 8.04.1.
  • Extensible management services allow you to customize an interface into a new tab.
  • An Eclipse™ plug-in helps you package applications and create management services.
  • Automatic dependency resolution for application packages installed on Linux-based virtual appliances.
  • Existing VM build (input-as-VM) for Linux virtual appliances.
  • DMTF standard OVF 1.0 and open virtual appliance (OVA) packaging. VMware Studio 1.0 supported OVF 0.9.
  • Eclipse usability improvements.
  • Appliance updates from CDROM.
  • Web console footer customization in the appliance VM.
  • EULA first-boot display control in the appliance VM.
  • Host name editing in the Web console of the appliance VM.
  • Security fix for VMware Studio when uploading management services. See CVE-2009-2968.

Just download it and try it out!

vSphere VM Snapshots and block size

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As some already noticed; when creating a snapshot on a VM with two disks the block size of the VMFS volume which hold the working directory is checked before the snapshot is taken. As reported by VMTN User Pizang this was not the case in ESX 3.x. You can imagine that this can cause issues when the second disk of a VM is larger than the maximum file size dictated by the block size of the VMFS file system which holds the working directory of the VM. What? Yeah I had to read that sentence at least 3 times before I understood what I said… This might make it easier:

virtualmachine001
Disk01 – 10GB stored on VMFS001 with a 1MB Block size
Disk02 – 350GB stored on VMFS002 with a 4MB Block size

VMFS001 contains the working directory of the vm “virtualmachine001”. Snapshots are stored in the working directory. In the case of Disk02 this could mean that the delta file grows beyond the maximum file limit of 256GB of VMFS001 where it will be stored.

Another example of where the block size could limit you is outlined in this KB article: http://kb.vmware.com/kb/1012384.

The proof is in! (vSphere Quick Start Guide)

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As most of you hopefully know by now we are working on a vSphere Quick Start Guide. We’ve been very busy the last couple of weeks getting it finalized. As you can imagine with VMworld coming up we are working against a very tight deadline. Thomas Bryant has been doing most of the formatting for the book and ordered a proof copy which has just arrived:

Source: The proof is in!


The first copy of our new book, vSphere 4.0 Quick Start Guide, has arrived! I’m very excited about the work everyone has done. It’s been a pretty rough ride at times, but it’s worth it in the end to see your name in print. I’m looking forward to getting a few copies for VMworld 2009!

Great work Duncan, Dave, Stu, Alan & Bernie!