top 6 vmware vsphere design questions

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Top 6 VMware vSphere Design QuestionsA discussion of design considerationsScott Lowe, VCDX #39vSpecialist, EMC CorporationAuthor, Mastering VMware vSphere 4Blogger, http://blog.scottlowe.orghttp://twitter.com/scott_lowe

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My “top 6” vSphere design questions

Should I…

• use a distributed or standard vSwitch?

• run vCenter as a virtual machine?

• use blades or rack mount servers?

• choose ESX or ESXi?

• put all my hosts into a single large cluster?

• lump all my VMs into one big LUN?


Question #1:Should I use a distributed vSwitch or a standard vSwitch?

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Distributed vSwitch or standard vSwitch?• Do you need to delegate network

configuration or the advanced functionality a dvSwitch offers?

• Trade convenience for additional considerations– Network configuration now dependent upon

vCenter Server– Affects running vCenter Server as a VM

• Requires Enterprise Plus licensing

• A “hybrid” approach utilizing both vSwitches, where possible, provides the best of both worlds


Question #2:Should I run vCenter Server as a virtual machine?



vCenter Server physical or virtual?• Both options are fully supported by VMware

• Virtual has advantages (can leverage HA, for example)

• Physical has advantages (no dependencies on the infrastructure it manages)

• Virtual introduces new considerations:– Need vCenter for dvSwitch control plane– What if vCenter is VM and runs across dvSwitch?– Creates circular dependency– Operational concerns with DRS, EVC, VUM


Question #3:Should I use blades or rack mount servers?



Blades or rack mount servers?• From a compute perspective, it’s a wash

• The impact falls primarily in high availability– Must consider HA cluster size and cluster

members per chassis– Can’t use redundant cards in blades in many

instances (no redundant NICs or HBAs)

• Newer blades offer as much connectivity as many rack mount servers (12 NICs, dual HBAs)

• More exotic connectivity (InfiniBand, FCoE, PCIe extenders) not as widespread


Question #4:Should I choose VMware ESX or VMware ESXi?



VMware ESX or VMware ESXi?• A common but not long-lived question

• vSphere 4.1 is the last version to contain VMware ESX; all future versions will use only ESXi

• So, perhaps a better question is, “How can I transition to ESXi?”

• One step is to familiarize yourself with the vSphere CLI and/or the vSphere Management Assistant

• If you’re a CLI junkie, get used to “vicfg-” instead of “esxcfg-”


Question #5:Should I put all my hosts into a single large cluster?



Large Clusters or Small Clusters?• There is no one right answer!

• Are you using blades?– Keep <5 cluster members per chassis– Must scale number of chassis to scale cluster size

• With vSphere 4.1 and VAAI, SCSI reservation conflicts are not a gating factor

• Clusters are not vMotion boundaries, only DRS/HA/FT organizational units


Question #6:Should I lump all my VMs together in one big LUN?



Few Big LUNs or Many Small LUNs?• LUN layout should be driven more by I/O

profile than capacity or number of VMs

• VAAI hardware-assisted locking eliminates SCSI reservation conflicts

• There are potential performance benefits to multiple LUNs (multiple queues per LUN)

• Less management overhead with fewer LUNs

• The key is proper storage design to accommodate I/O requirements


Q&A


THANK YOU

top 6 vmware vsphere design questions

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