VMware Cloud Provider – vSAN Best Practices

I’ve been getting a few requests recently on the best practices for vSAN inside of the Cloud Provider Program (VCPP). I’d like to spend some time on how VSAN works and on what works well within the consumption program.

First things first, how is vSAN licensed inside of VCPP?

vSAN consumes points just like any other offering inside of VCPP. However, compared to our bundles, vSAN is measured on Used Capacity on disk.

There are two base options of vSAN inside of VCPP:

  1. vSAN Standard
  2. vSAN Advanced

There are add-on packages for additional vSAN functionality. Essentially, this is added to the base option to provide additional feature sets. Two add-ons are available:

  1. Enterprise Add-On for the vSAN Standard base option
  2. Enterprise Add-On for the vSAN Advanced base option

This is all summarized in the Product Usage Guide (PUG as I call it) on page 45:

To summarize:

  1. vSAN Standard is 0.04 points/GB
  2. If I use vSAN Standard with the Enterprise Add-On: 0.06 points/GB (.02 uplift)
  3. vSAN Advanced is 0.06 points/GB
  4. If I use vSAN Advanced with the Enterprise Add-On: 0.08 points/GB (.02 uplift)

Now a single VCPP is equivalent to a specific cost, that’s all subject to your agreement. Moreover, Cloud Providers with higher commitments get additional discounts. This is on top of the current vSAN Promotion going on right now too. However, you can see how this can be attractive when we talk about consumption capacity and modeling.

vSAN Automatic Detection inside of vCloud Usage Meter

One of the great things about Usage Meter is it provides automatic detection of vSAN and will report on monthly consumption. This can be broken down to a specific tenant or customer based on your Usage Meter rule set.

There’s no additional configuration necessary to setup vSAN for Usage Meter reporting. Detected vSAN clusters will appear in the Cluster History report (depicted below).

Moreover, there are four features that are automatically detected based on the Usage Meter detection:

  1. Deduplication
  2. Erasure Coding (use of RAID5/6)
  3. Stretched Cluster
  4. IOPS Limit inside of the vSAN Storage Policy

There are a few things that are critical to accurate vSAN usage inside of VCPP:

  1. Ensure you are using the appropriate vSAN license key within the VCPP model. If you intend to use vSAN Advanced, use a vSAN Advanced key. Here’s why –
    1. Usage Meter will detect what license version of vSAN is being used. If an Enterprise key is detected, and either Dedupe/Erasure Coding features are being used, vSAN Advanced + Enterprise Add-On will be charged.
    2. This is important since if you are only intending to utilize vSAN Advanced (which includes Deduplication and Erasure Coding), you’ll want to make sure you pay for the appropriate amount.
  2. Stretch Cluster and Deduplication is applied at the cluster level. Hence, all workloads that reside on that vSAN datastore will be charged accordingly, even if you have workloads that may be tied to a PFTT=0 policy.
  3. Moreover, even individual features like IOPS limit and Erasure Coding (all within the SPBM) are enabled on a per-VM basis but scoped at the cluster level. If one or more VM’s are using these features, the feature is considered to be enabled for the entire cluster.

The below table showcases how vSAN is detected and the importance of using the accurate license.

vSAN Best Practices in VCPP

Here are a few things I’ve been messaging to my Providers regarding vSAN consumption inside of VCPP.

  1. vSAN is based on actual capacity used on disk. This is inclusive of the Fault Tolerance method used along with VM Memory Swap! Therefore, a FTT=2/RAID1 is going to consume a significant amount more storage than a FTT=1/RAID5EC policy.
    1. The chart that depicts storage capacity required for each FT method:
  2. VMs used the default Storage Policy are thin-provisioned while the VM Memory Swap is thick provisioned. Keep in mind when discussing this with eager tenants that like to over-provision their storage. vSAN will only consume the storage that has been written to disk.
  3. As for the VM Memory Swap, the Storage Policy does not impact the default setting. By default, VM Memory Swap is striped (or FTT=1) to another host. This can be overridden on a host basis by using the advanced setting of “esxcfg-advcfg -s 1 /VSAN/SwapThickProvisionDisabled”
    1. Review Duncan’s blog article more here: http://www.yellow-bricks.com/2016/02/29/vsan-6-2-sparse-swap-what-is-it-good-for/
  4. Deduplication and Compression can HELP from a cost perspective. Here’s why – Usage Meter will only detect what’s written to disk from the vSAN Cluster view. In the below example, I’ve written 101.72GB but with these efficiencies, I’ve written only 47.83GB to disk. From the VCPP program, I’d be only charged for about 47GB in space.
    1. ProTip: This is not a broad recommendation to use Deduplication and Compression just to save costs. Keep in mind the efficiencies only apply per disk group. Know your workload and I/O profile. This also applies to FTT policies – know your workload!

VCPP Sample Sizing for vSAN

So let’s go through some sample sizing on what an actual VM would be charged on a monthly basis.

Sample VM with FTT=1/RAID1 Policy

  • Sample VM: 2 vCPU, 4GB vRAM, 500GB HDD
  • SPBM – Standard Policy, FTT=1/RAID-1
  • Size Calculation
    • 500GB * 2 (FTT=1/RAID1) = 1000GB
    • 4GB Memory * 2 (Always mirrored) = 8GB
    • 1000GB + 8GB = 1008GB in total storage required
  • VCPP Cost Calculation – let’s say we are using the vSAN Advanced license which is .06 points per GB.
    • 1008GB * .06 points = 60.48 points per month
    • Let’s say my cost for a point was $1USD, this workload would cost me about $60 dollars a month.

Now let’s calculate this with an FTT=1/RAID5EC Policy. Keep in mind, all design rules apply still: still need a minimum of 4 hosts, dedupe/comp requires All Flash, etc.

Sample VM with FTT=1/RAID5/EC Policy

  • Sample VM: 2 vCPU, 4GB vRAM, 500GB HDD
  • SPBM – Standard Policy, FTT=1/RAID-5 Erasure Coding
  • Size Calculation
    • 500GB * 1.33 (FTT=1/RAID5EC) = 665GB
    • 4GB Memory * 2 (Always mirrored) = 8GB
    • 665GB + 8GB = 673GB in total storage required
  • VCPP Cost Calculation – let’s say we are using the vSAN Advanced license which is .06 points per GB.
    • 673GB * .06 points = 40.38 points per month
    • Let’s say my cost for a point was $1USD, this workload would cost me about $40 dollars a month. This is about a 32% reduction in savings compared to a RAID-1 policy. 

Now let’s say I applied a 1:5:1 deduplication and compression ratio to this sample VM. This is a conservative estimate since our standard vSAN calculator utilizes a 2:1 ratio.

Sample VM with FTT=1/RAID5/EC Policy with Deduplication/Compression Ratio of 1.5:1

  • Sample VM: 2 vCPU, 4GB vRAM, 500GB HDD
  • SPBM – Standard Policy, FTT=1/RAID-5 Erasure Coding
  • Size Calculation
    • 500GB  / 1.5 (dedupe/comp ratio) *1.33 (FTT=1/RAID5EC) = 443GB
    • 4GB Memory * 2 (Always mirrored) = 8GB
    • 443GB + 8GB = 451GB in total storage required
  • VCPP Cost Calculation – let’s say we are using the vSAN Advanced license which is .06 points per GB.
    • 451GB * .06 points = 27.08 points per month
    • Let’s say my cost for a point was $1USD, this workload would cost me about $27 dollars a month. This is about a 55% reduction in savings compared to the original model and 33% savings compared to the RAID5EC policy. 

Summary

  1. As you can see, vSAN consumption can be extremely granular from a cost perspective and will vary based on the protection scheme.
  2. Using the efficiency capabilities of vSAN along with Erasure Coding does save capacity, but remember what your workload requires!
  3. Usage Meter auto detects usage and will roll it up in the monthly reports – no additional configuration needed.
  4. As for pricing, there is a current promotion going on for vSAN inside of the Cloud Provider Program – reach out to your aggregator or VMware Business Development Manager for further information. This makes the overall vSAN pricing even more attractive on a consumption basis.

Cheers!

-Daniel

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