14 Common Virtualization Mistakes & How To Avoid Them - ASPE

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14 Common Virtualization Mistakes & How To Avoid Them - ASPE

you need all the hardware that is available by default? For example, do I have any need for the floppy drive inmy VM running some server product? The answer is probably “no” unless you are using some application thatwants to have a floppy image for license purposes.Mistake #8: Failing to have a backup planLet’s say that something happens, and your host or VM crashes. What are your plans then? What kind of workwas the VM doing? Can you afford to live without this VM? Most probably, the answer is no. So, do you haveanother machine that will take over in case the primary machine fails? This would imply that there was a machineready to go in case of a failure. Maybe you just have the VM in a shared storage, and you have some kindof fault tolerance mechanism that will kick in and another host will revive that dead VM by restarting it on adifferent host. Consider the downtime involved; if you have a standby machine, it will kick in within moments ofwhen the original VM goes down. But with fault tolerance, the VM will have to be restarted on a different host.There is the delay involved in restarting the machine.Mistake #9: Improper storage allocationA common issue that folks run into is committing a certain amount of disk storage for the VMs but never reallyfilling up the virtual drive. If you don’t have a need for it, maybe you shouldn’t have pre-allocated that storage.For example, VMware’s virtualization product allows you to allocate the storage on demand. This is called thethin provisioning mechanism. For example, if you specify a hard drive size for your VM to be 500 GB but onlyhave 50 GB of content, then it will only consume 50 GB storage space and will grow to 500 GB as needed. Thinprovisioning is provided to you by the VMware product and is one of the commonly ignored features, but itcould save you when it comes to storage and storage related cost. Remember to be careful not to over-commitsome storage drive. What would happen if all your VMs started growing and get near the maximum space allocatedto them? Do you have enough space available for all of them?Mistake #10: Poorly planned host management solutionHow are you managing your ESXi hosts from VMware? How are you managing your VMs on these ESXi hosts?If you only have one or two hosts, then maybe you can connect directly to your ESXi host to mange them, butwhat if you have many ESXi hosts? If that’s the case, then you need some kind of a central management solution.In case of VMware, you have the vCenter implementation. This will definitely make managing your ESXihosts easier as well as many other features that are covered in a VMware’s Install, Configure, and Manage class.Mistake #11: Lack of a plan for managing the virtual environmentSince we are talking about management, who will be managing the virtual environment? Is it going to be theWindows team, or your router team, or your security team, or who knows? Since the VMware product and othersimilar virtualization vendors are touching almost every single thing, such as networking with switches, securityimplementation, and storage, maybe there could be disagreements on whose territory is it. I would have a separategroup within my Active Directory domain for VMware admins, and it is separate from the Windows Administratorsgroup to avoid any confusion. This way, Windows Admin group can manage Windows and another group(vSphere Admins) can administer vSphere related components for the Virtual Machines.Copyright ©2011 Global Knowledge Training LLC. All rights reserved. 4


About the AuthorDheeraj (Raj) Tolani has been working with Global Knowledge as a contract instructor teaching various courses,including authorized VMware training. He has been in the industry for over 18 years working with various technologies,including Cisco, Banyan Vines, Microsoft, Novell, and VMware. Dheeraj has worked as a consultant forvarious medical, financial, legal, government, and publishing companies. He runs a consulting company based inNew York City providing IP integration solutions (www.rajtolani.com).Copyright ©2011 Global Knowledge Training LLC. All rights reserved. 6

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