With `ephemeral_disk`, is the persistent `alloc` dir global to all datacenters?

From the docs:

“All tasks in this group will share the same ephemeral disk.”

Since the task groups may span any number of datacenters, I assume the alloc dir to be persisted across datacenters. Is this correct?

Hi @salvor,

Ephemeral disks are not simultaneously persisted across multiple clients. When an allocation is first placed on a client, the allocation directory structure will be built. In the event this allocation fails the local/ and alloc/data directories will be moved/copied depending on where the replacement allocation is placed and how the ephemeral disk in configured.

Datacenters are an abstract concept whereby a client can exist within a single datacenter and an allocation can be eligible for scheduling on any array of datacenters, but only placed within a single one.

I hope this helps. Please let me know if you have any followup questions.

jrasell and the Nomad team

Sorry for my vague question, and thanks for taking the time!

Correction: ‘are ephemeral_disks locked into a DC, or given a sufficient need for it, will the scheduler migrate between available DCs?’

I think the language on the docs indicates that migration between DC’s happens seamlessly, but I was just curious to hear if I was perhaps wrong.