Error "Capacity Utilization" is seen on vSAN Quick Start tab when adding a Compute-Only host to the cluster.
Article ID: 392526
Updated On:
Products
Issue/Introduction
- While adding a compute-only host to a vSAN datastore via "Quick Start", after the configuration is completed, the error "Capacity Utilization" is seen on step 3 of the "Quick Start" tab.
- When cross-checking on Skyline Health, the error related to the "Capacity Utilization" is related to the "Limits - Host component" check. This can be seen as a Yellow Warning or a Red Danger.
Environment
VMware vSAN 8.x
VMware vSAN 7.x
VMware vSAN 6.x
Cause
There is a limit to the number of components a vSAN Node can have.
If the "Limits - Host component" check returns a warning or error, it means that the number of vSAN components is reaching its ESXi host limit. Once the components per host limit has been reached, the deployment of new virtual machines fails, and rebuild operations cannot be completed.
These are the thresholds at which warnings and errors are displayed for this health check:
Green (OK) --> Less than 80%
Yellow (Warning) --> Between 80% - 90%
Red (Danger) --> More than 90%
The maximum component number in a vSAN cluster is limited to 288000
The maximum number of components per vSAN OSA host is 9000.
The maximum number of components per vSAN ESA host is 27000.
Resolution
To resolve this problem, there are the option below:
- Add additional hosts with Disk-Group(s) to the cluster.
- Reduce the number of components by utilizing storage policies that require fewer components (e.g. FTM=RAID1 instead of FTM=RAID5 or StripeWidth=1 instead of StripeWidth=4),
- Please note, this may result in more storage space being required, any policy changes should be done in batches and not be done en-masse to prevent contention/performance issues.
- The number of components can be reduced by deleting any data objects that are confirmed to be no longer needed.
Important Note:
To have components placed on an additional host, the host has to be contributing to the vSAN datastore. As mentioned above, the host to be added has to have disk-groups created also. A compute-only node will not resolve this issue.
Additional Information
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