Short answer: The vSphere 8.0 Update 3 release notes announced the deprecation of Storage I/O Control (SIOC), the Storage DRS I/O load balancer and SDRS I/O reservations-based balancing. vCenter 9.0 then discontinued them. SIOC limits set through SPBM storage policies and Storage DRS space-based placement and balancing are not affected. vSphere 7.x and 8.x keep the full functionality. Network I/O Control (NIOC) is a separate feature and is not part of this change.
What the vSphere 8.0 U3 release notes say
The deprecation notice is in the VMware vCenter Server 8.0 Update 3 release notes. It names three components: the SDRS I/O Load Balancer, the SDRS I/O Reservations-based load balancer, and “vSphere Storage I/O Control Components”. The notes also say which parts stay: space-based initial placement and balancing, and SPBM policy settings for limits.
The follow-up came with VCF 9.0. The vSphere product support notes for VCF 9.0 list it under End of Support: vCenter 9.0 discontinues support for these components. So in 9.x this is no longer a warning. The features are gone.
What is removed and what stays
| Capability | vSphere 7.x / 8.x | vCenter 9.0 and later |
|---|---|---|
| Enabling SIOC on a datastore (latency-based congestion control) | Supported (deprecated from 8.0 U3) | Not supported |
| SIOC shares and reservations in SPBM storage policies | Supported (deprecated) | Not supported |
| SDRS I/O latency-based load balancing | Supported (deprecated) | Not supported |
| SDRS I/O reservations-based load balancing | Supported (deprecated) | Not supported |
| SDRS initial placement and balancing on space | Supported | Supported |
| IOPS limits in SPBM storage policies | Supported | Supported |
The IOPS limit keeps working because the host’s disk scheduler enforces it, not the datastore-wide SIOC congestion logic. In the vSphere Client it still sits under the Storage I/O Control policy component, which is why people often assume it is going away too.
Before upgrading to vSphere 9 or VCF 9
- Find datastores with SIOC enabled and datastore clusters with I/O metric balancing enabled.
- Review VM storage policies that use SIOC shares or reservations. Replace them with policies that only set IOPS limits, or with none.
- Check scripts, Terraform or Aria/VCF Automation templates that set SIOC or SDRS I/O options. Broadcom warns that workflows and automation may need updates.
- Decide how you will handle noisy neighbours after the upgrade (see below).
A quick PowerCLI inventory:
# Datastores with SIOC enabled
Get-Datastore | Where-Object {$_.StorageIOControlEnabled} | Select-Object Name, Type
# Datastore clusters with SDRS I/O load balancing enabled
Get-DatastoreCluster | Select-Object Name, SdrsAutomationLevel, IOLoadBalanceEnabledSIOC vs NIOC: is Network I/O Control affected?
No. Neither the 8.0 U3 release notes nor the 9.0 support notes mention NIOC. Network I/O Control version 3 runs on the vSphere Distributed Switch. It allocates uplink bandwidth with shares, reservations and limits per system traffic type (vMotion, NFS, iSCSI, vSAN, Fault Tolerance, management, VM traffic and others). Total reserved bandwidth across system traffic cannot exceed 75 percent of the slowest physical adapter.
For IP storage (NFS, iSCSI, NVMe/TCP), NIOC now does much of the contention control that SIOC used to do at the datastore level, at least for the network part of the path. It does not see array-side latency, though. Physically separating storage and vMotion traffic onto dedicated uplinks is still the more deterministic option. I cover this in VCF 9 SAP HANA network design: why 6 NICs matter for vMotion and NFS, and you can compare the layouts interactively in SAP HANA on VCF 9: TDI network design and vNIC simulator.
Alternatives for noisy-neighbour control
- SPBM IOPS limits per VM or per VMDK. Still supported, and the most direct replacement for capping a known offender.
- Array QoS (per volume, LUN or vVol). The array sees real back-end latency, which ESXi cannot.
- vSAN storage policy IOPS limit for vSAN datastores.
- NIOC shares and reservations for NFS and iSCSI traffic on the VDS.
- Placement: spread heavy workloads across datastores. SDRS space balancing and initial placement still help.
If you run NFS datastores, also look at nConnect support in the ESXi NFS client to spread load across multiple TCP connections.
Further reading
- Duncan Epping (Yellow Bricks): Storage IO Control, aka SIOC, deprecation notice with 8.0 U3! (the original post this page used to point to)
- Broadcom TechDocs: vCenter Server 8.0 Update 3 release notes
- Broadcom TechDocs: VCF 9.0 vSphere product support notes
- VMware Cloud Foundation blog: Storage DRS and Storage IO Control deprecations
- Broadcom TechDocs: What is vSphere Network I/O Control
