What are your thoughts on "Upgrade Pool"

TrueNAS General
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2

You already understand the “risks”.

Upgrading a pool is a one-way operation.

The only way to assure you can “undo” an upgrade is to create a checkpoint before you go through the upgrade and RAIDZ expansion process.

Keep in mind that you’re not meant to write any new important data (that you wish to keep)[1] after the checkpoint’s creation, if you plan to immediately rewind back to the checkpoint.

TL;DR:

  1. You create a checkpoint
  2. You upgrade the pool
  3. You expand your RAIDZ vdev
  4. You immediately regret it :scream:
  5. You rewind back to the checkpoint.
  6. Everything from steps 2 through 3 “never happened”

Alternative TL;DR:

  1. You create a checkpoint
  2. You upgrade the pool
  3. You expand your RAIDZ vdev
  4. You like the results :slightly_smiling_face:
  5. You discard the checkpoint

:warning: Understand the nuances of checkpoints, and the differences between importing pools on TrueNAS vs vanilla ZFS.

  1. That’s why if you write new files between steps 2 through 3, you will lose them after rewinding to the checkpoint. ↩︎

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