Author Archives: workinghardinit

Lightning Fast Fixed VHDX File Creation Speed With ReFS on Windows Server 2016

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In this blog post we’re going to take a quick look at the lightning fast fixed VHDX file creation speed with ReFS on Windows Server 2016. We’ll compare it to creating fixed VHDX files On NTFS with a SAN that supports ODX. Both the NTFS and the CSV volume are CSV disk in a Hyper-V cluster and the test is run on the same node. The ODX cabale SAN is a Dell Compellent with Storage Center 6.5.20.

We create on  a selection of fixed VHDX files sizes (50GB, 100GB, 500GB and 1TB) on NTFS volume Windows Server 2016 host You can see the quite excellent results in file creation speeds with ODX.

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These results are very good (DELL Compellent always did a great job implementing ODX) and the time to create a 1TB fixed VHDX is just over 5 seconds consistently. Impressive by any standard I would say! When we start using CSVs we can see that times double for the larger VHDX sizes but still +/- 12seconds for a 1TB disk is impressive by any standard. There is little difference whether the node where the script runs owns the CSV or not.

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Can things be more impressive? Let’s do the same exercise on a ReFS volume on a Windows Server 2016 host. Same server, same SAN with ODX enabled but note that ReFS does not even support ODX, so it cannot be leveraged.

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No matter what the file size of our fixed VHDX files they are created in just over 1 second consistently. This is very impressive.

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When we use a CVS LUN we still see the same impressive results. On CSV LUNS not owned by the node where we execute the test script we see a creation time of 2 seconds for VHDX sizes of 1TB. Still lightning fast.

If you do not have a SAN that supports ODX you can see why ReFS might become a very attractive choice for the file system for your Hyper-V virtual machine data volumes in Windows Server 2016. I can see why they mentioned it as the preferred option for Storage Spaces Direct. Do note that ReFS does not support deduplication and/or UNMAP (I see no dedupe support yet for virtual server workloads on the horizon either yet?). If you move large amounts of data around ODX does provide significant assistance with this. So with ReFS go for a large SSD tier. Flash only without deduplication or erasure coding might be cost prohibitive I’m afraid.

But let this not put you off ReFS. It has many benefits in combination with storage spaces and these new VHDX operation capabilities just add to that. So for many environments with commodity based storage this has become an even more interesting choice.

The Hitch Hikers Guide to Hyper-V Administration: Don’t Panic

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Not all information you might see or is presented to you is valid. You need to check, that’s the prime reason we have the “trust but verify” mantra in IT. If you don’t you might start trouble shooting a ghost issue. An example of this are GUI issues, such as when you leave the Hyper-V Manager GUI open for way to long and the information goes stale in the cache.

The below screen shot is what caused some diligent admins to start trouble shooting a non existent problem. The figured that the VMs were left in a locked state due to backups failing. But hey, all backups had run and succeeded?! So they searched and found  KB article 2964439 Hyper-V virtual machine backup leaves the VM in a locked state. When they wanted to install the hotfix it failed stating it was not applicable to their system.

At that moment they considered killing the VMMS.exe service and/or failing over the nodes. While preparing for that they’d logged in to all nodes, only to see the issue not present there. That made ‘m think and step back for a while.

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In this case it’s just a quirk with the Hyper-V manager that is left open way to long. Right click the host and refresh or close the GUI and reopen it is all that’s needed to see the real information.

So slow down before you start trouble shooting & recovering form a “ghost” problem. It may cause real issues. The lesson here is you should not go into the “Action Jackson” mode. You can move swift and efficient but the ability to execute does not constitute just speed it doing what’s needed when and when needed. Here ends the lesson Smile

Windows Server 2016 Technical Preview Version 3 Cluster Upgrades

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I was eagerly awaiting the release of Windows Server 2016 Technical Preview 3 for further experimenting and testing and August 19th 2015was the big day with a truck load of announcements and press releases including the arrival of TPv3 which also made containers publicly available for testing to all of us.

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After a swift download II set out upgrading the labs, both PC hardware based and enterprise grade server hardware. I always test out the less wise things as well just to kick the tires and test behavior left and right.

As always I tested some in place upgrades just to see how well that goes before doing clean installs . Not recommend in production but hey,Testing is good. At first all networking seem to be OK but it wasn’t. So I ended up with doing clean installs which are advisable, even more so with non production versions of the OS. The product is not finished yet! This is also the supported way of doing a new cluster build. imageThe end result is a lab at home on PC hardware and an enterprise grade lab to work with in the datacenter. Busy times ahead.

For help on what’s new in this build go here What’s New in Windows Server 2016 Technical Preview 3 and good luck on your Windows Server 2016 Technical Preview Version 3 cluster upgrades!

Happy testing!

Get-ClusterLog Got Better In Windows Server 2016

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When the going get’s tough the tough get going. But that doesn’t mean we don’t like and edge or won’t take advantage of tools and features that make our job easier.

In Windows Server 2016 Failover clustering Microsoft added some features to do just that when it comes to troubleshooting.

This is what Get-CusterLog does for you: it writes the FailoverClustering/Diagnostics events to a cluster.log file on every member node of that cluster. Collecting them all form there is tedious so they gave us the –destination parameter to set a common target folder on the host where we run the command.

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So unless you get paid by the hour you’d normally you’d run Get-ClusterLog with the –Destination parameter so all the cluster logs from all cluster members are dumped into the destination folder for your.  But in Windows Server 2016 they went the extra mile.  More often than not other event logs are asked and needed. So a great improvement here is that this command now dumps all the relevant other channels into the cluster.log files generated and separates them out via a “header” [===LOGINQUESTION ===]

We now find following logs included:
[=== Microsoft-Windows-ClusterAwareUpdating-Management/Admin logs ===]
[=== Microsoft-Windows-ClusterAwareUpdating/Admin logs ===]
[=== Microsoft-Windows-FailoverClustering/DiagnosticVerbose ===]
[=== System ===]

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This saves a lot of time as more often than not those are asked for and needed to troubleshoot. Note the DiagnosticVerbose log. This is a permanent parallel event channel that logs the verbose information. This avoids the overhead of having to set the logging level of the normal Diagnostic log to verbose and trying to reproduce the issue. Pretty cool, the info is there and it doesn’t cause the standard logging to roll over faster as that logs at the default level.

We also get the cluster objects listed in the log now to help with diagnosing issues.

[=== Resources ===]
[=== Groups ===]
[=== Resource Types ===]
[=== Nodes ===]
[=== Networks ===]
[=== Network Interfaces ===]
[=== Volume ===]
[=== Volume Logs ===]

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Another improvement is that the log now indicates the offset against UTC or allows you to specify the –UseLocalTime parameter to get you the log in the time settings of the server. Both these options can be handy correlating events.

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I’m happy with these efforts to gather the information needed to diagnose an issue easier and faster. It’s not about perfection but making progress and that what’s happening.