vSAN Disk Group Expansion

[kevlab]

Author : william rogers

URL : http:////docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.virtualsan.doc/GUID-F1A01098-B538-...

Topic Name : Add a Capacity Device

Publication Name : Administering VMware vSAN

Product/Version : VMware vSphere/6.7

Question :

Can I add a different size SSD to an existing disk group? Currently I have 1 x 480GB for cache and 4 x 480GB for capacity. Am I able to add lets say 2 x 1TB drives to the disk group? Or should I create a completely new disk group? (This will be done the same for each host on the cluster).

[sk84]

Basically it is supported. But I would recommend to create another disk group. But you should be aware that it can have a negative performance impact and in case of a rebuild of the whole disk group (e.g. if the cache device fails) the remaining disk groups should have enough space to hold the larger amount of data. And if you increase the capacity part of the disk group you should also look that the cache size is still large enough for your workload.

Maybe these links will help you:

Designing vSAN Disk groups - All Flash Cache Ratio Update - Virtual Blocks

Using differently sized disks in a VSAN environment

Disk Group Design

[depping]

moving this to the appropriate sub community: vSAN.

And I agree with the above comment, it is not a best practice but it is supported for all the reasons above.