vCenter 7 nervous about free space

[srodenburg]

On a 2-node Cluster (back2back) with 3 HDD's each, which has it's vSAN Datastore filled to 73%, the "vSAN Capacity Utilization, disk space" Alert is already in a warning state. If i'm not mistaken, that threshold "Warning" used to be 80% in 6.x

Is this a bug? Why start complaining at 73% ?  It's a 2 node after all.

[Dave Morera]

The 80% is the automatic rebalance threshold. I believe the 30% vSAN cluster capacity has been in place for some time now.

[srodenburg]

Yeah I read that about an hour after I posted my post :-)  Both 6.7 and 7.0 say 30%.

Them 30% is a bit "conservative" eh?  Customers always complain about needing to buy so much % more storage than the usable capacity that they need and vSAN throws salt in that would by requiring so much "overhead" (as that's how customers tend to interpret it).

On a normal cluster, this makes sense as there needs to be space on other nodes for rebuilds in case of "node-death". On 2-Nodes however, there is no place to go so those 30% and "What if the most consumed host fails" Alert are rather pointless. I'd say get rid of the latter alert on 2-node and up the free space threshold to 85% or so...