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Failover Clustering
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Cluster Shared Volume - A Systematic Approach to Finding Bottlenecks

Elden_Christensen's avatar
Elden_Christensen
Icon for Microsoft rankMicrosoft
Mar 15, 2019

Part 7

First published on MSDN on Jul 29, 2015 In this post we will discuss how to find if performance that you observe on a Cluster Shared Volume (CSV) is what you expect and how to find which laye...
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Updated Dec 12, 2024
Version 8.0
cluster shared volumes
csv series
vladimir petter
kwester-ebbinghaus-business's avatar
kwester-ebbinghaus-business
Iron Contributor
Jun 23, 2020

Elden_Christensen thanks for your article. 

I have question in this regard. 

 

"64K is the recommended allocation unit size with NTFS and 4k with ReFS."

 

"A rule of thumb might be to simply use the same cluster size as block size used by the storage layer.  Always consult your storage vendor for advice, modern storage arrays have very sophisticated tiering and load balancing logic and unless you understand everything about how your storage box works you might end up with unexpected results. Alternatively you can run variety of performance tests with different cluster sizes and see which one gives you better results. If you do not have time to do that then I recommend 64k block size."

 

 

Why the different recommendation of yours for ReFS 4k vs 64k NTFS for a CSVFS hosting Hyper-V disks?

I see other recommendations with Server 2019 (newer version of ReFS) to use ReFS for CSVFS using ReFS instead of NTFS, for gaining the best performance (creation of VHDX / creation and merge of Snapshots) etc, which I can confirm to be more performant over NTFS.