Storage Policy Based Management uses these rules to describe the storage requirements of a VM. When one changes on vSAN, the change is rolled out in asynchronous batches, not all at once.
Also called VM storage policy.
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Each book explains storage policy in context, with comparison tables and the common traps.
Terms in this definition
- Storage Policy Based Management
vSphere's mechanism for pairing each VM's storage needs, captured in VM storage policies, with suitable datastores and data services, while reporting whether VMs comply.
- Description (Image Analysis 3.2)
Visual feature in Image Analysis 3.2 that produces natural-language caption sentences sorted by confidence, read from Description.Captions[0].Text. Version 4.0 swaps it for Caption.
- General-purpose v1
The older storage account kind (
Storage), which lacks access tiers, Archive and premium file shares and retires on 13 October 2026. Converting to ZRS requires first upgrading to GPv2, a one-way change. - vSAN
VMware's software-defined storage, which combines local devices across a cluster's ESX hosts into one shared datastore. Available as OSA or ESA, VCF can use it as principal storage.
- ALL
A DAX function that ignores any filters and gives back every row of a table or every value of the named columns. Used within CALCULATE, it works as a modifier that clears filters, although REMOVEFILTERS states that intent more clearly where it is available.
- Once flow
A flow that executes a single time and repeats only if the pipeline is fully refreshed. It's a common choice for a first full load ahead of a change feed, and that refresh becomes dangerous once the original files no longer exist.
Related terms
- Compliance engine
Reports Compliant or Non Compliant for every entity under a storage policy, according to whether Prism Central finds the transformation has really happened.
- Effective free space
The amount of free capacity vSAN reports once a chosen storage policy and the fault domain layout are taken into account. Expect it to be below the raw disk free space.
- Flash read cache reservation
Only meaningful in hybrid vSAN OSA clusters (ESA and all-flash OSA ignore it), this storage policy rule sets aside read cache on flash for a VM object, sized as a percentage of that object's logical size.
- Live vDisk migration
Relocating the vDisk of a running VM to a different storage container, perhaps to change data reduction or replication factor. A VM under a storage policy cannot do this.
- Number of disk stripes per object
vSAN ESA already uses three stripes for RAID-0 and RAID-1 objects; this storage policy rule sets the minimum number of capacity devices over which each copy of an object is spread, between 1 (default) and 12. More stripes may help performance but consume more resources, and the documentation recommends leaving it at the default.
- PVC
Short for PersistentVolumeClaim, this is how Kubernetes workloads ask for storage, naming a class, a size and an access mode. On vSphere Supervisor, a PVC created after the class's storage policy has been dropped from the namespace will fail.
- Replication factor
The count of data copies held by a storage container, chosen for each container or storage policy. Do not mix it up with cluster fault tolerance, the setting for surviving failures.
- Storage policy encryption
Encrypting a VM or volume group by means of a storage policy. There is no going back: it stays on after being enabled.