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Sep 28 2014

How to enable Nutanix De-duplication per VMDK/VHD/RAW

The Nutanix performance tier de-duplication allows the sharing of VM data on premium storage tiers (RAM and SSD). Performance of guest VMs suffers when active data can no longer fit in these premium tiers. Nutanix also provides de-duplication for the capacity tier (HDD) for greater VM density.

Nutanix de-duplication is 100% software defined, with no controllers or hardware crutch; and this feature is available for all supported hypervisors (vSphere, Hyper-V and KVM).

The capacity tier de-duplication is a post-process de-duplication, meaning the common blocks are aggregated according to a curated background process; by default every 6 hours, while de-duplication in the performance tier is real-time, meaning it happens as data blocks transverse RAM or Flash. This hybrid de-duplication approach allows Nutanix Controllers to be less intrusive and utilize less CPU cycles to detect common data blocks.

To learn more about the de-duplication process read Nutanix 4.0 Hybrid On-Disk De-Duplication Explained.

 

Via the PRISM UI the on-disk capacity de-duplication is enabled on a per Container basis. However, it is also possible to enable and disable de-duplication per VMDK, VHD and RAW (vDisk) using the NCLI. That could be very useful when you want to de-duplicate a set of VMs, but not the entire datastore.

 

First identify the vDisk to be de-duplicated using : ncli> vdisk list

 

To edit the vDisk properties you will use vDisk edit with the name identifies in the previous command.

 

Please note that to enable on-disk-dedup, fingerprint-on-write must also be turned on and only fingerprinted data is considered for post-process de-duplication during curator full scans. Background dedup jobs are scheduled in a rate limiting fashion and do not impact cluster performance.

 

This article was first published by Andre Leibovici (@andreleibovici) at myvirtualcloud.net

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