VMware vSAN on Consumer-Grade SSDs – Endurance analysis

When you are running an ESXi based homelab, you might have considered using vSAN as the storage technology of choice. Hyperconverged storages are a growing alternative to SAN-based systems in virtual environments, so using them at home will help to improve your skillset with that technology.

To get started with vSAN you need at least 3 ESXi Hosts, each equipped with 2 drives. Alternatively, you can build a 2-node vSAN Cluster using a Raspberry Pi as a witness node.

VMware has created a special HCL that lists supported drives to be used with vSAN. In production setups, it is very important to use certified hardware. But how bad is it to use inexpensive consumer SSDs?

This article takes a look at consumer-grade SSDs and their capability to be used with vSAN. Please be aware that non-certified hardware should only be used in homelabs or for demo purposes.

All-Flash or Hybrid vSAN?

I highly recommend to no longer use Hybrid vSAN in Homelabs. We are close to 2021 and magnetic disks are more and more vanishing. If you are planning to use vSAN you should go All-Flash.

Cache and Capacity Endurance (TBW)

There are two types of disks used in All-Flash vSAN – Capacity and Cache. In All-Flash, the cache layer is used for write-buffering only. Everything that is written to the vSAN Datastore is written to the cache and destaged later to the capacity tier. Currently, there is no way to run vSAN on a single disk, or omit the caching layer.

A couple of months ago, I’ve created a 2-node vSAN Cluster using two Intel NUCs and migrated the majority of my virtual machines from a shared storage to vSAN. This includes a vCenter Server, NSX-T components, Tanzu Kubernetes components, and a couple of management VMs. The see how vSAN affects my SSDs endurance (TBW) I’ve modified my NVMe TBW Monitoring Script to send data to Graphite.

With the collected metrics, I calculated how much GB is written per hour and day.
As shown in the graph, vSAN has written about 300 GB per day to the Caching Tier and 20GB per day to the Capacity tier. With this data, it is safe to say that you do not have to worry about the Capacity Tier’s endurance. Do get an idea of what 300GB/day means for the SSDs endurance, I did some calculations:

  • 3.5 MB per second
  • 213 MB per minute
  • 12.5 GB per hour
  • 300 GB per day
  • 8.8 TB per month
  • 107 TB per year
  • 535 TB in 5 years

When buying SSDs, the vendor gives a guarantee in years and “TBW” (Terabytes Written). With most vendors, the guarantee expires when either 5 years have passed, or more data than specified in TBW has been written to the drive.

With my vSAN setup, I need an SSD with at least 535 TBW, not calculation any growth.

Choosing SSD for vSAN

When choosing SSDs for vSAN you typically would buy a small SSD for caching, and a large SSD for the capacity tier. When using consumer hardware, it might be a good idea to also use a large SSD for caching, as the endurance grows with the size of the device.

The following table shows capacity and TBW values of commonly used consumer grade SSDs:

Vendor Product Name Capacity TBW Warranty
Samsung 980 PRO NVMe M.2 SSD 250 150 5 years
Samsung 980 PRO NVMe M.2 SSD 500 300 5 years
Samsung 980 PRO NVMe M.2 SSD 1000 600 5 years
Samsung 950 PRO NVMe M.2 SSD 256 200 5 years
Samsung 950 PRO NVMe M.2 SSD 512 400 5 years
Samsung SSD 870 QVO SATA III 2.5 Inch 1000 360 3 years
Samsung SSD 870 QVO SATA III 2.5 Inch 2000 720 3 years
Samsung SSD 870 QVO SATA III 2.5 Inch 4000 1440 3 years
Samsung SSD 870 QVO SATA III 2.5 Inch 8000 2880 3 years
Samsung 970 EVO Plus NVMe M.2 SSD 250 150 5 years
Samsung 970 EVO Plus NVMe M.2 SSD 500 300 5 years
Samsung 970 EVO Plus NVMe M.2 SSD 1000 600 5 years
Samsung 970 EVO Plus NVMe M.2 SSD 2000 1200 5 years
Samsung 860 QVO SATA III 2.5 Inch SSD 1000 360 3 years
Samsung 860 QVO SATA III 2.5 Inch SSD 2000 720 3 years
Samsung 860 QVO SATA III 2.5 Inch SSD 4000 1440 3 years
Samsung 970 EVO NVMe M.2 SSD 250 150 5 years
Samsung 970 EVO NVMe M.2 SSD 500 300 5 years
Samsung 970 EVO NVMe M.2 SSD 1000 600 5 years
Samsung 970 EVO NVMe M.2 SSD 2000 1200 5 years
Samsung 970 PRO NVMe M.2 SSD 512 600 5 years
Samsung 970 PRO NVMe M.2 SSD 1000 1200 5 years
Samsung 860 EVO SATA III 2.5 Inch SSD 250 150 5 years
Samsung 860 EVO SATA III 2.5 Inch SSD 500 300 5 years
Samsung 860 EVO SATA III 2.5 Inch SSD 1000 600 5 years
Samsung 860 EVO SATA III 2.5 Inch SSD 2000 1200 5 years
Samsung 860 EVO SATA III 2.5 Inch SSD 4000 2400 5 years
Samsung SSD 860 PRO SATA III 2.5 Inch 256 300 5 years
Samsung SSD 860 PRO SATA III 2.5 Inch 512 600 5 years
Samsung SSD 860 PRO SATA III 2.5 Inch 1000 1200 5 years
Samsung SSD 860 PRO SATA III 2.5 Inch 2000 2400 5 years
Samsung SSD 860 PRO SATA III 2.5 Inch 4000 4800 5 years
Samsung 860 EVO SATA III M.2 SSD 250 150 5 years
Samsung 860 EVO SATA III M.2 SSD 500 300 5 years
Samsung 860 EVO SATA III M.2 SSD 1000 600 5 years
Samsung 860 EVO SATA III M.2 SSD 2000 1200 5 years
Intel Intel Optane Memory 16GB 16 182.5 5 years
Intel Intel Optane Memory M10 16GB 16 365 5 years
Intel Intel Optane Memory 32GB 32 182.5 5 years
Intel Intel Optane Memory M10 32GB 32 365 5 years
Intel Intel Optane SSD 800P 58GB 58 365 5 years
Intel Intel Optane SSD 800P 58GB 118 365 5 years
Intel Intel® 545s-SSDs 256 144 5 years
Intel Intel® 545s-SSDs 512 288 5 years
Intel Intel® 545s-SSDs 256 144 5 years
Intel Intel® 660p-SSDs 512 100 5 years
Intel Intel® 660p-SSDs 1024 200 5 years
Intel Intel® 660p-SSDs 2048 400 5 years
Intel Intel® 760p-SSDs 128 72 5 years
Intel Intel® 760p-SSDs 256 144 5 years
Intel Intel® 760p-SSDs 512 288 5 years
Intel Intel® 760p-SSDs 1024 576 5 years
Intel Intel® 760p-SSDs 2048 576 5 years
Transcend PCIe SSD 220S 256 550 5 years
Transcend PCIe SSD 220S 512 1100 5 years
Transcend PCIe SSD 220S 1000 2200 5 years
Transcend PCIe SSD 220S 2000 4400 5 years
Seagate IronWolf 510 240 435 5 years
Seagate IronWolf 510 480 875 5 years
Seagate IronWolf 510 960 1750 5 years
Seagate IronWolf 510 1920 3500 5 years


Posted by Editor