gibarra94
Enthusiast
Enthusiast

vSan Failure test

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Hi everyone!

I have a production Stretched Cluster with vSan and we need to do the following test:

  1. Create a storage Policy with Raid 1 cross site and Raid 0 intra site
  2. Assignt it to a vm "test-vm"
  3. Simultate a failure on ESXi-01 (for example) with only the "test-vm" virtual disk on it, and monitoring the behaviour on the vm.

So, my question is "How can i move all data of the production vm's to other hosts, and force only the virtul disk of test-vm resides on the ESXi-01 host disk group?

Thank You!

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lucasbernadsky
Hot Shot
Hot Shot

Hi, Gustavo. after doing some research I couldn't manage to find anything similar to "Disk Groups affinity rules", which I think it is what you need. VSAN places the components across diskgroups but you cannot decide in which one. I would recommend you to select a VM, check which disk groups it's objects are running, move all compute workloiads from there and only leave the hosts contributing storage to the cluster. Finally reboot the hosts and take a look at the cluster behaviour and how vSAN marks the object as absent for a few minutes.

Please note that the VM will remain accesible only if it has FTT > 0.

I know this is not the best option for you. Maybe the closest approach for waht you need is to remove only one object component and track how it is rebuild but I couldn't find information about how to only remove one component without deleting the entire object.

Get object UUID: https://www.virtuallyghetto.com/2017/11/translating-vsan-vm-object-ids-uuid-to-vm-and-vm-to-uuid.htm...

Remove inaccesible objects: https://www.thinkcharles.net/blog/2018/2/16/removing-inaccessible-objects-in-vsan

Regards!

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lucasbernadsky
Hot Shot
Hot Shot

Hi, Gustavo. after doing some research I couldn't manage to find anything similar to "Disk Groups affinity rules", which I think it is what you need. VSAN places the components across diskgroups but you cannot decide in which one. I would recommend you to select a VM, check which disk groups it's objects are running, move all compute workloiads from there and only leave the hosts contributing storage to the cluster. Finally reboot the hosts and take a look at the cluster behaviour and how vSAN marks the object as absent for a few minutes.

Please note that the VM will remain accesible only if it has FTT > 0.

I know this is not the best option for you. Maybe the closest approach for waht you need is to remove only one object component and track how it is rebuild but I couldn't find information about how to only remove one component without deleting the entire object.

Get object UUID: https://www.virtuallyghetto.com/2017/11/translating-vsan-vm-object-ids-uuid-to-vm-and-vm-to-uuid.htm...

Remove inaccesible objects: https://www.thinkcharles.net/blog/2018/2/16/removing-inaccessible-objects-in-vsan

Regards!

View solution in original post

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gibarra94
Enthusiast
Enthusiast

Thank you very much for your answer!

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TheBobkin
VMware Employee
VMware Employee

Hello Lucas,

Just for clarification - you can't delete a portion/replica/component of an Object using objtool, only entire Objects (whether they are healthy/accessible or not).

Bob

lucasbernadsky
Hot Shot
Hot Shot

Thanks, Bob! Nice to have the confirmation

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