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Objects are still Healthy but some of them that had components on the esx04 have just lost one copy. I was not able to evacuate all data from the host because of the lack of free space, so I used “Ensure Accessibility” option. Well done vSAN! Datastore is almost full, but objects are healthy Ultimate test I am able to power off VMs, run some management activities. Hosts are fully responsive, vCenter as well. It looks like vSAN will not allow to get 100% full, it queues some activities. Other VMs run fine.Īt this point rebalancing is scheduled but not running, because datastore is getting full so there is no point in doing this. ![]() It looks like datastore full test affected also my vRLI VM that was probably writing new datastore full logs on its VMDKs. I deliberately run fio 100% sequential write test on them to invoke this process. Now some of thin provisioned VMs are stunned. VMs are working fine (especially those that do not write to disks much) but at this point we will not be able to create new VMs (+ FTT-1 mirror policy requires 2 copies of data ). vCenter Alarm definitionsĭatasore view and vSAN Capacity view turned red. If we do not modify alarm settings, we will get a warning at 75% usage and Critical at 85%. Datastore size doesn’t seem to be full now but this is a summary of all of the datastores in the cluster, not only the vSAN datastore.Įnd now a very popular datastore alarm appears: “Datastore Usage on disk”. With one host offline there will be no free space on datastore to create VMs. vSAN Health vCenter viewīecause more data is filling up this datastore, a Warning turns into an Error. vSAN Health shows a Warning that if we now loose one of the hosts in a cluster, disk space utilization will be high. We are informed in a very early phase that something is going on with our datastore. How to fill a datastore with data? Usually I am using HCI Bench that creates lots of VMs with lots of thin provisioned VMDKs and let it run for a while. ![]() I always wanted to test it and now I have some time to do this. Long story short – vSAN has always handled it very well but with 6.7 U3 we get lots of additional new guardrails. Every admin knows that monitoring free space on EVERY datastore is critical but it doesn’t mean we are not curious how the system reacts when datastore gets full. The question: what happens when vSAN datastore gets full, is a very common one but rarely we have an option to test it. “ This release includes new robust handling of capacity usage conditions for improved detection, prevention, and remediation of conditions where cluster capacity has exceeded recommended thresholds.“ Reading Release Notes for vSAN 6.7 U3 you might overlook a very important improvement that was introduced with this release: Increased hardening during capacity-strained scenarios.
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