How much downtime should we plan per gateway, and why is automation faster than manual?

Plan a 1–2 hour maintenance window per gateway. The automated Ansible run itself usually takes only 15–30 minutes; the rest of the window is your verification and recovery budget. Manual migrations are slower mainly because operators spend that budget fixing out-of-order steps instead of checking the next one.

What is the single most important pre-flight check before migrating?

Confirm `CachePercentDirty` is 0 and that every application writing to the gateway is stopped. If the cache is dirty when volumes detach, writes that have not yet flushed to Amazon S3 are lost permanently, and no automation recovers them. The playbook only warns about this, so verify it yourself.

Will clients have to remount their file shares after migration?

Only if the gateway is referenced by neither a DNS name nor an Elastic IP. The new AL2023 instance gets a new private IP. With a DNS name, update the record afterward; with an EIP, disassociate from the old instance and associate to the new one. Decide this before you start, or you risk a fleet-wide remount.

At what point does the migration stop being reversible?

The migration API call is the boundary. Before it (Ansible steps 1–9) the operation is fully reversible by reattaching volumes to the old instance using the saved device-mapping file. After it (step 10 onward) you only get automatic retry, not rollback. Never run `terraform destroy` post-success, as that deletes the new gateway.

What IAM permission does the gateway lookup actually require?

The migration needs `storagegateway:DescribeGatewayInformation` so the helper script can resolve the gateway ID to its EC2 instance. If you hit "Can't find EC2 instance ID," check that permission, the gateway ID, and that `jq` is installed, in that order — not exotic EC2 mutate permissions the procedure never requests.

AWS Storage Gateway AL2023 Migration: Why You Automate or Bleed

Wed, 17 Jun 2026 00:00:00 +0000

On paper this reads like a chore: an operating-system version bumps, you reboot a few appliances, you move on. That framing is what gets fleets in trouble. The real stakes show up when you multiply one routine rebuild by a few hundred gateways sitting under a hard date, and the "chore" becomes a sequencing problem that can quietly lose data.

Version on StorageNews

AWS Storage Gateway AL2023 Migration: Why You Automate or Bleed