Datastore access impaired

[J-Philippe]

Hello just looking for some help / advices about this warning that I faced sometimes.

I'm not sur to fully undertsand the root cause of this warning and the solution to provide.

Any help will be appreciate.

Regards,

Jean-Philippe

[DeclanOR · Accepted solution]

Hi @J-Philippe 

Please ignore my previous comment if you saw it. I was refencing the incorrect alarm type :)

Datastore access impaired is basically an alert to say that access to a datastore has been lost by an OVC.

This can be expected if you reboot and OVC or reboot a host etc.

If you see this issue more regularly, it can be a sign of an underlying network issue, or other potentially bigger issues, and a support case should be raised to review your environment.

Hope this helps.

Thanks,

DeclanOR

[J-Philippe]

Thanks Declan,

strange because for me this behavior match with the VM daa access not optimized. I mean when VM A running on Node 1 but data location is on node 2 and 4 for example.

Does it mean the datastore impaired warning is the same kind of alarm ?

[J-Philippe]

Ok thank you Declan, I  better understand now :-)

[Convergo]

When having vSphere HA turned on in vSphere Availablity services, one of the cluster settings are Heartbeat Datastores. In a for example 2 node cluster, once one node is down the heartbeat datastores are unavailable. Is this by design and what would be the best setting to use: Automatically select datastores accessible from the hosts, use datastores only from the specified list or Use datastores from the specified list and complement automatically if needed ?

[Sanika]

Hi @Convergo ,

You are right, in a 2-node cluster with vSphere HA enabled, if one node goes down, the heartbeat datastores will be unavailable. This is by design.

vSphere HA uses datastore heartbeating to distinguish between hosts that have failed and hosts that reside on a network partition. When a node is down, it cannot access the datastore, regardless of the configuration.

Now, regarding the best setting for Heartbeat Datastores in a 2-node cluster:

1.  Automatically select datastores accessible from the host – This is the simplest option and requires no manual configuration. The heartbeat datastores are automatically selected by vSphere HA based on accessibility and performance

2. Use datastores only from the specified list – This option allows you to manually select specific datastores for heartbeating. Only those datastores selected from the list of datastores will be used for datastore heartbeating. If one of those datastores becomes unavailable, vSphere HA will not perform datastore heartbeating through a different datastore.

3. Use datastores from the specified list and complement automatically if needed – In this option, the administrator selects the preferred datastores that vSphere HA should use for datastore heartbeating. vSphere HA will automatically choose the alternative accessible datastores from that list. If one of the datastores becomes unavailable, vSphere HA will choose a different datastore. When none of the preferred datastores are available, vSphere HA will choose any available cluster datastore.

According to me, if you are using a 2-node cluster, the best option for heartbeat datastores in your scenario is the first option mentioned above "Automatically select datastores accessible from the host". Because this option allows vSphere HA to automatically choose any shared datastores accessible by all hosts in the cluster avoiding the need for manual configuration.

Here are some additional resources that you might find helpful:
https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.avail.doc/GUID-3E042A65-9E2A-4966-B838-0E24FA54286A.html
https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.avail.doc/GUID-0502B198-F5F7-4101-969C-C5B6F364C678.html
https://geek-university.com/datastore-heartbeating-explained/

Hope this works for you.

Regards,
Sanika.

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[Convergo]

Hi Sanika,

thanks for your detailed explanation. With SimpliVity nodes however there is only an option to use SimpliVity datastores.