How to migrate a mimir cluster into a cortex cluster

[friedrich-at-adobe]

Is your feature request related to a problem? Please describe.
Document how to migrate from mimir into cortex

Describe the solution you'd like
A documentation explaining step by step how to migrate a mimir into a cortex cluster

Additional context
Folks need to know if they are going to have any pitfalls migrating from mimir.

[stevedef]

@friedrich-at-adobe How did you migrate in the end?

[friedrich-at-adobe]

@stevedef It was cortex v1.13.0 to mimir v2.3.0 and back to cortex v1.13.0
The process was very straight forward.

• Redeploy all ingesters, compactors, store gateways and alertmanagers first with cortex image and updated flags.
• do rulers, queries next. let them finish
• do query-frontend last.

found one tiny compactor issue that is linked, but it was easy to fix. Data was not lost. All history was preserved.
I didn't use any of the experimental out of order support or the mimir compactor new flags though.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[alanprot]

/remove stale

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[yeya24]

Let's move this to 1.17 release