How to expand ZFS on FreeBSD

Running out of disk space is one of the leading causes of IT outages. In this blog post, I will show you how to expand storage on FreeBSD with ZFS. ZFS works as volume manager and filesystem.

Datacenter Power Costs and Their Impact in the Virtualized World

I recently conducted a quick analysis of a VMware vSphere–based virtual datacenter for a customer, and here’s what I found.

The average monthly electricity consumption of a single vCPU with ~3 GB vRAM is 1.4 kWh, which translates to approximately $0.4  

The datacenter of my customer is located in Central Europe, and they pay 0.33 USD for 1 kWh of electricity in a Tier 3 datacenter facility (UPS + cooling included in energy cost).

Here are my questions for the broader worldwide infrastructure community.

• Q1: How much do you pay for electricity in your data center or server facility?
• Q2: What are the statistics of your cluster (CPU, memory, # of VMs, # of vCPUs, # of vRAM)?
• Q3: How much power do your physical servers consume on average?

For vSphere Cluster statistics, you can use the PowerCLI script Get-ClusterDensity. I use it to compare virtual cluster metrics (# of VMs, # of vCPUs) with the actual power consumption of physical servers, which you can obtain from your hardware’s management tools.

If you want to dive deeper into my quick analysis, read on.

Password expiration for both the VCSA root user and the vSphere administrator

Password expiration for both the VCSA root account and the vSphere administrator (typically administrator@vsphere.local) is a common issue, especially if the default 90-day expiration settings are overlooked. It recently happened to me in one lab environment. Fortunately, both passwords can be recovered. This blog post outlines the recovery methods that worked in my case.

vSAN ESA RAID5 issue? Not really, but ...

I was observing unexpected behavior in my vSAN ESA cluster. I have a 6-node vSAN ESA cluster and a VM with a Storage Policy configured for RAID-5 (Erasure Coding). Based on the cluster size, I would expect a 4+1 stripe configuration. However, the system is using 2+1 striping, which typically applies to clusters with only 3 to 5 nodes.

RAID-5 (2+1) striping is using 133% of the raw storage

RAID-5 (4+1) striping is using 120% of the raw storage

A 13% difference is worth investigating.

vSAN ESA RAIDs

vSAN ESA is VMware’s software-defined storage solution. Each virtual hard disk (vDisk) is represented as an object within the vSAN datastore. The properties of these vSAN objects are governed by vSAN VM Storage Policies, which define data placement and protection rules. While these policies may emulate traditional RAID (Redundant Array of Independent Disks), vSAN actually implements RAIN (Redundant Array of Independent Nodes). This is because data components, such as stripes and replicas, are distributed across failure domains, which by default correspond to vSphere/vSAN cluster nodes (ESXi hosts). The specific striping and distribution are determined by the configured failures-to-tolerate policy and vSAN cluster size.

vSAN ESA supports multiple levels of RAID/RAIN (Redundant Array of Independent Nodes) for data protection:

• RAIN-0: No redundancy (data is not protected)

• RAIN-1: Mirroring (1+1) across two nodes

• RAIN-5: Erasure coding with a 2+1 or 4+1 configuration (minimum 4 or 6 hosts)

• RAIN-6: Erasure coding with higher fault tolerance, typically 4+2, but can also be 6+2 or 8+2 depending on cluster size

These options allow you to balance storage efficiency, performance, and fault tolerance based on your specific workload and cluster topology.

How do I check the build or version number of VMware ESX?

The ESX build (version number) information is available in the Summary tab of the vSphere Client, but in larger environments it is worth to use some kind of automation. PowerShell/PowerCLI is well know scripting tool for VMware vSphere.

Below is PowerCLI one-liner to easily query all vCenters where you are connected ...

Get-VMhost | Select-Object Name,Version,Build 

If you want connect to vCenter(s) interactively, you can use following script ...

# Connect to vCenter
Write-Host "Connecting to vCenter ..."
$VC = Read-Host "Enter one vCentre Server or multiple vCenter servers delimted by comma."
Write-Host "Enter vCenter credentials ..."
$CRED = Get-Credential
Connect-VIServer -Server $VC -Credential $CRED -ErrorAction Stop | Out-Null

VMwareOpsGuide.com has been retired

I'm an architect and designer, not involved in day-to-day operations, but I firmly believe that any system architecture must be thoughtfully designed for efficient operations, otherwise the Ops team will go mad in no time.

Over the years, I’ve been learning a lot from the book VMware Operations Management by  Iwan E1 Rahabok, which covers everything related to vROps, Aria Operations, and now VCF Operations.