Tag Archives: cost

Example Architectural Decision – Transparent Page Sharing (TPS) Configuration for VDI (2 of 2)

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Problem Statement

In a VMware vSphere environment, with future releases of ESXi disabling Transparent Page Sharing by default, what is the most suitable TPS configuration for a Virtual Desktop environment?

Assumptions

1. TPS is disabled by default
2. Storage is expensive
3. Two Socket ESXi Hosts have been chosen to align with a scale out methodology.
4. Average VDI user is Task Worker with 1vCPU and 2GB Ram.
5. Memory is the first compute level constraint.
6. HA Admission Control policy used is “Percentage of Cluster Resources reserved for HA”
7. vSphere 5.5 or earlier

Requirements

1. VDI environment costs must be minimized

Motivation

1. Reduce complexity where possible.
2. Maximize the efficiency of the infrastructure

Architectural Decision

Enable TPS and disable Large Memory pages

Justification

1. Disabling Large pages is essential to maximizing the benefits of TPS
2. Not disabling large pages would likely result in minimal TPS savings
3. With Kiosk and Task worker VDI profiles, the percentage of memory which is likely to be shared is higher than for Power users.
4. Existing shared storage has plenty of spare Tier 1 capacity to vSwap files

Implications

1. Sufficient capacity for VM swap files must be catered for.
2. VDI & Storage performance may be impacted significantly in the event of memory contention.
3. Decreased memory costs may result in increased storage costs.
4. During patching, and operational verification that non default settings have not been reverted by the patching of ESXi.
5. Additional CPU overhead on ESXi from enabling TPS.
6. HA admission control will calculate fail-over requirements (when using Percentage of cluster resources reserved for HA) so that performance will be approximately the same in the event of a fail-over due to reserving the full RAM reserved for every VM,
6. HA admission control (when configured to Percentage of Cluster resources reserved for HA) will only calculate fail-over capacity based on 0MB + VM overhead for each VM which can lead to significantly degraded performance in a HA event.
7. Higher core count (and higher cost) CPUs may be desired to drive overcommitment ratios as RAM will be less likely to be a point of contention.

Alternatives

1. Use 100% memory reservation and leave TPS disabled (default)
2. Use 50% memory reservation and Enable TPS and disable large pages

Related Articles:

1. The Impact of Transparent Page Sharing (TPS) being disabled by default @josh_odgers (VCDX#90)

2. Example Architectural Decision – Transparent Page Sharing (TPS) Configuration for VDI (1 of 2)

3. Future direction of disabling TPS by default and its impact on capacity planning –@FrankDenneman (VCDX #29)

4. Transparent Page Sharing Vulnerable, Yet Largely Irrelevant – @ChrisWahl(VCDX#104)

Taking vSphere to the Next Level with Converged Infrastructure – vForum2013

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At this months vForum in Sydney, Australia, I will be presenting “Taking vSphere to the Next Level with Converged Infrastructure”.

The session discusses where the virtualization market is today along with problems that exist along the journey to 100% virtual and how converged infrastructure helps solve these challenges allowing vSphere architects and administrators to take their virtual environments to the next level.

The session is scheduled for Day 2 of the conference (October 22nd) at 11AM in Parkside 110A room.

I invite everyone who will be at vForum Sydney to attend the session, and for those of you who cannot make the event, the presentation will be posted on this blog along with follow up articles covering any questions from the session.

 

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

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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