Example Architectural Decision – Default Virtual Machine Compatibility Configuration

Problem Statement

In a VMware vSphere 5.5 environment, what is the most suitable configuration for Virtual Machine Compatibility setting at the Datacenter and Cluster layers?

Assumptions

1. vSphere Flash Read Cache is not required.
2. VMDKs of greater than 2TB minus 512b are not required.

Motivation

1. Reduce complexity where possible.
2. Maximize supportability.

Architectural Decision

Configure the vSphere Datacenter level “Default VM Compatibility” as “ESXi 5.1 or later” and leave the vSphere Cluster level “Default VM Compatibility” as “Use datacenter setting and host version” (default).

Justification

1. Avoid limiting management of the environment to the vSphere Web Client.
2. The Default VM Compatibility only needs to be set once at the datacenter layer and then all clusters within the datacenter will inherit the desired setting.
3. Reduce the dependency of the Web Client in the event of a disaster recovery.
4. As vFRC and >2TB VMDKs and vGPU are not required, there is no significant advantage to HW Version 10.
5. Ensuring a standard virtual machine compatibility level is maintained throughout the environment and reducing the chance of mismatched VM version types in the environment.
6. Simplicity.

Implications

1. Virtual Machine Hardware Compatibility automatic update must be DISABLED to prevent the VM hardware being automatically upgraded following a shutdown.
2. vSphere Flash Read Cache (vFRC) cannot be used.
3. VMDKs will remain limited at 2TB minus 512b.

Alternatives

1. Virtual Machine HW Version 10 (vSphere 5.5 onwards).
2. Virtual Machine HW Version 8 (vSphere 5.0 onwards).
3. Virtual Machine HW Version 7 (vSphere 4.1 onwards).
4. Older Virtual machine HW versions.

 

Storage DRS Configuration – Architectural Decision making flowchart

I was speaking to a number of people recently, who were trying to come up with a one size fits all Storage DRS configuration for a reference architecture document.

As Storage DRS is a reasonably complicated feature, it was my opinion that a one size fits all would not be suitable, and that multiple examples should be provided when writing a reference architecture.

A collegue suggested a flowchart would assist in making the right decision around Storage DRS, so I took up the challenge to put one together.

The below is my version 0.1 of the flowchart, which I thought I would post and hopefully get some good feedback from the community, and create a good guide for those who may not have the in-depth knowledge or experience, too choose what should be in most cases an appropriate configuration for SDRS.

This also compliments some of my previous example architectural decisions which are shown in the related topic section below.

As always, feedback is always welcomed.

I hope you find this helpful.

* Updated to include the previously missing “NO” option for Data replication.

SDRS flowchart V0.2

Related Articles

1. Example Architectural Decision – Storage DRS configuration for NFS datastores

2. Example Architectural Decision – Storage DRS configuration for VMFS datastores

Example Architectural Decision – Advanced Power Management for vSphere Clusters with Business Critical Applications

Problem Statement

In a vSphere environment where Business Critical Applications have been successfully virtualized, should Advanced Power Management be used to help reduce data center costs?

Requirements

1. Fully Supported solution

2. Reduce data center costs where possible

3. Business Critical Application performance must not be significantly degraded

Assumptions

1. Supported Hardware

2. vSphere 5.0 or later

3. Admission Control is enabled with >= N+1 redundancy

Constraints

1. None

Motivation

1. Reduce Datacenter costs where possible with minimal/no impact to performance

Architectural Decision

Configure the BIOS to “OS Controlled”

Set ESXi Advanced Power Management to “Balanced”

Justification

1. Power savings can be realized with almost no impact to performance

2. The performance difference between “High performance” & “Balanced” options is insignificant however Power savings can be achieved reducing cost and environmental impacts

3. In the unlikely event of performance issues as a result of using the “Balanced” option, the BIOS is set to OS Controlled so ESXi can be updated without downtime during troubleshooting

4. Advanced Power Management Options (other than “High Performance” & “Balanced”) have proven to have excellent power savings but at a high cost to performance which is not suitable for Business Critical Applications

5. As HA Admission Control is used to provide >=N+1 redundancy, the ESXi hosts will generally not be fully utilized which will give Advanced Power Management opportunities to conserve power

6. The workloads in the cluster/s run 24/7 however demand is generally higher during business hours and some low demand or idle time exists

7. Even where only a small power saving is realized, if performance is not significantly impacted then a faster ROI can be achieved due to cost savings

Implications

1. Where performance issues exist using “Balanced” a vSphere administrator may need to change Advanced Power Management to “High Performance”

Alternatives

1. Use “High Performance”

2. Use “BIOS Controlled”

3. Do not use Advanced Power Management

4. Use Advanced Power Management in conjunction with DPM

Relates Articles

1. Power Management and Performance in ESXi 5.1 – By Rebecca Grider (@RebeccaGrider)

 AdvancedPowerManagement