What is the SPBM file format?
An .spbm file is an internal data file belonging to VMware vSphere's Storage Policy Based Management (SPBM) framework. SPBM is the vSphere component that lets administrators define abstract storage policies - specifying requirements such as RAID failure tolerance, encryption at rest, thin or thick provisioning, and caching behavior - and then automatically enforce those policies when virtual machines and virtual disks are deployed or migrated across datastores.
The .spbm file stores the policy definitions and the bindings between those policies and virtual machine storage objects (.vmdk disks). It lives on a datastore as part of vSphere's internal bookkeeping and is not intended to be opened or edited directly. Administrators manage SPBM through the vSphere Client UI or via the vSphere Storage Policy API documented in Broadcom's TechDocs portal.
The format is proprietary and its internal structure has not been publicly documented; it is versioned with the vSphere release cycle rather than as a standalone standard. SPBM was introduced with vSphere 5.x around 2012 and is now integral to the VMware Cloud Foundation (VCF) platform following Broadcom's acquisition of VMware in 2023.
Companion files in a vSphere environment include .vmx (VM configuration) and .vmdk (virtual disk descriptor).
Security & safety
RISK: LOWInternal VMware infrastructure file; not executable. Only relevant in vSphere environment; no end-user security risk.
Format details
in a nutshellPrograms that open SPBM files
Windows2 apps
VMware vSphere Client
Paid Manage storage policies through vSphere Client → Policies and Profiles → VM Storage Policies. Do not attempt to open .spbm files directly.
VMware PowerCLI
Free Use Get-SpbmStoragePolicy / Get-SpbmCompatibleStorage cmdlets to query SPBM policies programmatically. Technical details
deep spec| Framework | VMware vSphere Storage Policy Based Management (SPBM) |
| Developer | VMware, Inc. (now Broadcom, following 2023 acquisition) |
| MIME type | application/octet-stream |
| Internal encoding | Proprietary - internal structure not publicly documented (suspected XML or protobuf) |
| Typical file size | Kilobyte range (stores policy metadata, not VM data) |
| Stored content | Storage policy definitions, capability metadata, and policy-to-VMDK binding records |
| Policy parameters | RAID failure tolerance, encryption at rest, thin/thick provisioning, caching, and data services |
| Platform | Windows (vSphere management), Linux (ESXi host) |
| Management interface | vSphere Client UI or vSphere Storage Policy API (Broadcom TechDocs) |
| Version dependency | Tied to VMware vSphere / VMware Cloud Foundation (VCF) release cycle; no independent versioning |
| User interaction | Internal datastore artefact - not opened or edited directly by end users |
| Companion formats | .vmx (VM configuration), .vmdk (virtual disk descriptor), .vmsd (snapshot metadata) |
| Released | ~2012 (vSphere 5.x with SPBM framework introduction) |
| Latest version | Tied to VMware vSphere release (vSphere 8.x / VCF 5.x current) |
| Specification | techdocs.broadcom.com |
SPBM conversions
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