On my blog article for yesterday “Rob M” commented that the default affinity rule for Storage DRS (SDRS), keep VM files together, did not make sense to him. One of the reasons this affinity rule is set is because customers indicated that from an operational perspective it would be easier if all files of a given VM (vmx / vmdk’s) would reside in the same folder. Especially troubleshooting was one of the main reasons, as this lowers complexity. I have to say that I fully agree with this, I’ve been in the situation where I needed to recover virtual machines and having them spread across multiple datastore really complicates things.
But, just like Rob, you might not agree with this and rather have SDRS handling balancing on a file per file basis. That is possible and we documented this procedure in our book. I was under the impression that I blogged this, but just noticed that somehow I never did. Here is how you change the affinity rule for the current provisioned VMs in a datastore cluster:
- Go to Datastores and Datastore Clusters
- Right click a datastore cluster and select “edit settings”
- Click “Virtual machine settings”
- Deselect “Keep VMDKs together”
- For virtual machines that need to stick together you can override the default by ticking the tick box next to the VM
Also check out this article by Frank about DRS/SDRS affinity rules, useful to know!