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Deduplication block level factor

  • 13 March 2023
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Hello,

In  the documentation Deduplication Building Block Guide (commvault.com), it is mentioned that:

“The DDBs created for Windows Media Agent should be formatted at 32 KB block size to reduce the impact of NTFS fragmentation over a time period.”

Is the format at 32 KB referring to the block size of the disk itself (NTFS block size) or referring to the “Block Level Deduplication Factor” parameter of the Storage Policy as shown below ?

Thanks

 

 

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Best answer by NVFD411 13 March 2023, 19:47

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@brucquat - The documentation is referring to the allocation unit size (also know as the cluster size) of the NTFS filesystem used by the disk.  This is because using a smaller allocation unit size can lead to more fragmentation on the disk over time, which can negatively impact performance. By using a larger allocation unit size, such as 32 KB, the impact of fragmentation on performance can be reduced.

Userlevel 2
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Hi,

Thanks but practically, we should format the disk where the DDB resides on to 32KB AND also change the block level deduplication factor to 32KB or leave it to 128KB ?

Thanks

Userlevel 2
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@brucquat - Recommendation would be to use 128KB for block level deduplication on the CV side.

 

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