Tag: PowerShell

Data Deduplication in Windows Server 2019

When Windows Server 2016 was released, Data Deduplication was not available for ReFS file system, and only available for NTFS. With Windows Server 2019, data deduplication is now available for both NTFS and ReFS file systems.

Data Deduplication is a great technology that allows you to reduces your storage footprint by removing any duplicated data blocks and replacing it with metadata.

In the scenario below, I will show you how to enable Data Deduplication and tracking the ‘saving rate’ of the data deduplication.

Install-WindowsFeature FS-Data-Deduplication

This cmdlet will allow you to install the feature. In most scenarios, ie. Storage Spaces Direct, Hyper-V, this will make most sense. Also, this cmdlet would need to be executed on all nodes.

Get-Command *Dedup*

Now that we have data deduplication installed, we can now see all the of the cmdlets available.

Enable-DedupVolume -Volume "E:","F:" -UsageType HyperV

Finally, once we enable data deduplication on the volumes, we can now track the saving rate. Note, this can be done via PowerShell, or Windows Admin Center (WAC). Note, this can only be enabled on Cluster Shared Volumes (CSV).

Get-DedupVolume

I hope this helps, and now you can start minimizing the data deduplication within your environment.

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System Center Operations Manager (SCOM) 2019- Requirements for Windows Server 2019 via PowerShell

The following PowerShell code is to install all the necessary IIS components for System Center Operations Manager (SCOM) 2019 Web Console on Windows Server 2019.

Import-Module ServerManager
Add-WindowsFeature Web-Server, Web-WebServer, Web-Common-Http, Web-Default-Doc, Web-Dir-Browsing, Web-Http-Errors, Web-Static-Content, Web-Health, Web-Http-Logging, Web-Log-Libraries, Web-Request-Monitor, Web-Performance, Web-Stat-Compression, Web-Security, Web-Filtering, Web-Windows-Auth, Web-App-Dev, Web-Net-Ext45, Web-Asp-Net45, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Mgmt-Tools, Web-Mgmt-Console, Web-Mgmt-Compat, Web-Metabase, NET-Framework-45-Features, NET-Framework-45-Core, NET-Framework-45-ASPNET, NET-WCF-Services45, NET-WCF-HTTP-Activation45, NET-WCF-TCP-PortSharing45, WAS, WAS-Process-Model, WAS-Config-APIs, web-asp-net -restart

You can also find this in Microsoft’s TechNet Gallery, HERE.

Deploy an Azure Cloud Witness for your Failover Cluster Quorum for Windows Server 2016 & 2019 with PowerShell

For the longest time, when deploying a cluster with Windows Server, you only had the two options,

  1. Using a dedicated disk for the quorum, or
  2. Configuring an SMB file-share as the quorum witness

With Server 2016 and 2019, there is now a third option, Cloud Witness. The Cloud Witness leverages Azure Blob storage to provide that additional cluster/quorum vote.

Before showing you how this is done, one should understand the purpose of a witness/quorum is with respect to a failover cluster.

When one or more members of a cluster stops reporting to the other cluster members, there is a vote. The vote ensures that there is no split-vote, and ensures the cluster has a true owner. For example, in a two node cluster, if each node believe it is the owner, then this will cause a “split-brain”. In short, neither node will ever agree it is the owner (or not). This is where a quorum is required to determine who is the owner by providing the third vote, ie. majority. This ensures the cluster has a true owner by having the majority of votes. Each member gets a vote, plus the quorum.

Why this matters, in the even there is no quorum, a node from the cluster can be evicted and as a result will suspend all application services to prevent data corruption by more than one system writing data without the cluster services coordinating data writes and access. Depending on policies, VMs running on the ejected cluster member will either suspend operations or be migrated to other nodes before being ejected.

Below is a step-by-step guide on how to configure the Azure Blob storage as the Cloud Witness.

Assumptions:

  • The Azure Blob storage account has already been created,
  • The cluster with at least 2 nodes already exists.

Launch the PowerShell console as Administrator, and execute the following cmdlet:

Set-ClusterQuorum -CloudWitness -AccountName "storage_account_name" -AccessKey "primary_access_key"

Now if we go back to the Failover Manager console we can see we have successfully configured cluster with a Cloud Witness.

In conclusion, deploying a Cloud Witness for a Failover Cluster is very simple, and in case of power outage in one datacenter, maintenance on a node, etc. then the entire cluster and its members (nodes) are all given an equal opportunity. Not only is it recommended and a requirement for 2-node clusters, but for any number of nodes, having a quorum is key ensuring high-availability.  As mentioned, there are the traditional options such as using a dedicated disk or a file-share (SMB) as the cluster witness. However with Azure Blob storage with its 16×9 uptime, we can always ensure the quorum witness is online and available.

DNS commands (Command Prompt vs PowerShell)

Recently I discovered Windows PowerShell has the ability to clear the local DNS on a machine, just like the traditional Command Prompt. Below is a table of the most common commands I personally use on a day-to-day basis and its PowerShell equivalent(s). Of course there are more PowerShell cmdlets, see the URL below for the complete list.

Command Prompt PowerShell Description
ipconfig /flushdns Clear-DnsClientCache Clears the contents of the DNS client cache.
ipconfig /registerdns Register-DnsClient Registers all of the IP addresses on the computer onto the configured DNS server.
ipconfig /displaydns Get-DnsClientCache Retrieves the contents of the DNS client cache.
 

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Flush DNS Cache with PowerShell

For years I have always been using Windows’s command prompt to flush the DNS cache on a local machine. As we know, that command is pretty well known, “ipconfig /flushdns“. Turns out there is an equivalent command we can run within the PowerShell console, and that is, “Clear-DnsClientCache“. Clear-DnsClientCache does exactly what it states, it clears the contents of the DNS client cache/local machine. Consider this next time you need to flush the local machine’s DNS cache.

Clear-DnsClientCache

Connect Batch of Azure VMs to Log Analytics (OMS) via PowerShell

So, you have a bunch of Virtual Machines (VMs) in Azure, and didn’t used an ARM template, and now need to connect the VMs to Log Analytics (OMS). Earlier this month, I demonstrated on this can be done with the ARM portal, here’s that blog post. Of course, this has to be done individually and can be very tedious if you have 10’s or 100’s of machines to do this to… All I can think of is PowerShell!

Here is a script I tweaked that Microsoft has already provided but for a single VM. I have just tweaked it to automate and traverse through your entire resource group, and add ALL VMs within the RG to Log Analytics.

Here is the link to Microsoft TechNet for that script. Please test it out and let me know. And if it helped you out, please give it a 5 start rating.

Microsoft TechNet PowerShell Gallery

If all went well, your before and after should look similar to this. I had two test VMs in my Resource Group.

Before:

After:

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Enabling SCOM 2016 Agent Proxy

Not too much has changed when it comes to SCOM 2012R2 and SCOM 2016. This post is a similar post to SCOM 2012R2, but applicable to SCOM 2016. (See that post here).

You could go to the computer that SCOM is complaining about and manually enable the agent proxy via Administration > Managed Computers, and modifying its properties, see below:

2

Or…… you could make your life easier, and do this…

The fix is easy, and the explanation are both below:

To resolve the “Agent proxy not enabled” alert for all machines in your current environment, run the following PowerShell code in the SCOM PowerShell Console:

get-SCOMagent | where {$_.ProxyingEnabled -match "False"} | Enable-SCOMAgentProxy

To prevent this alert in the future, run the following below:

add-pssnapin "Microsoft.EnterpriseManagement.OperationsManager.Client"; new-managementGroupConnection -ConnectionString:<strong>yourSCOMMGMTserverFQDNhere</strong>; set-location "OperationsManagerMonitoring::"; Set-DefaultSetting -Name HealthService\ProxyingEnabled -Value True