April 12, 2021

vSAN 7 Update 2 - Capacity Monitoring Advancements

Monitoring vSAN capacity is easier than ever in VMware vSAN 7 Update 2

vSAN administrators can seamlessly deploy applications and containers to a diverse set of protection levels and data services to a singular clustered pool of storage. Monitoring storage is much easier with a single datastore, but care still needs to be taken to monitor free space and project usage.  To accommodate this the vSAN capacity monitoring services have been continuously improved to help.

Storage Alerts

Complimenting the new space reservations introduced in 7 Update 1, vSAN 7 includes customizable warning and error thresholds. The default warning is at 70% and the default critical alarm is 90%.

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These alerts monitor the available capacity after operational reserve, and the host rebuild reserve has been removed from the total raw capacity.


Within the capacity monitoring, the ability to predict usable capacity based on a specific policy's raid protection level. This allows for the modeling of additional overhead for increases in resiliency or calculating space savings when moving from mirroring to erasure code style protection levels.

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In addition, oversubscription is now being tracked. This allows for modeling how much capacity is being saved by thin provisioning as well as deduplication and compression. This allows for quick visibility into worst-case expansion, as well as getting a clearer view into how effective thin provisioning is functioning.

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As a reminder, vSAN health also monitors free capacity and provides a warning if capacity is insufficient to handle a host failure.

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As you deploy vSAN 7 be sure to familiarize yourself with these operational tools to more efficiently manage capacity, and don't forget to consider the new compression-only clusters and UNMAP/TRIM to get the most capacity and performance out of your vSAN cluster.





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