Hakozume
Contributor
Contributor

On the fault tolerance of FTT=1

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My question is based on the assumption that FTT=1 is selected in VxRail.

Am I correct in assuming that if two nodes, one for production and one for mirror, fail and only the witness is alive and well, the VM will not be rebuilt and will go down?

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VM_Yamato
Enthusiast
Enthusiast

Hi @Hakozume -san, 

Thanks use VxRail cluster. 

FTT means "how many failure is acceptable on the vSAN cluster" and only one failure event is acceptable when you set FTT=1. (One disk failure, one host faiure, one NIC failure and etc)

and when you configure following storage policy, toatlly 3 components are created.

[Storage Policy]
 L RAID1 Mirror
 L FTT=1

Then, two components and one witness. (So you are right!)

and it the two components are not available, yes the VM will goes down. (Because in this case, two failure occured)

If you have any more question, please let us know. Thanks!

Yamato Sakai Technical Training Instructor | Dell Technologies Education Services

View solution in original post

1 Reply
VM_Yamato
Enthusiast
Enthusiast

Hi @Hakozume -san, 

Thanks use VxRail cluster. 

FTT means "how many failure is acceptable on the vSAN cluster" and only one failure event is acceptable when you set FTT=1. (One disk failure, one host faiure, one NIC failure and etc)

and when you configure following storage policy, toatlly 3 components are created.

[Storage Policy]
 L RAID1 Mirror
 L FTT=1

Then, two components and one witness. (So you are right!)

and it the two components are not available, yes the VM will goes down. (Because in this case, two failure occured)

If you have any more question, please let us know. Thanks!

Yamato Sakai Technical Training Instructor | Dell Technologies Education Services

View solution in original post