How to view the amount of storage used in a persistent volume?

Hello! I set up a Redis Fly container using the new guide here: Redis on Fly which requires provisioning a persistent volume to the Fly app to maintain data incase Redis restarts/crashes etc.

I set a fairly low volume size to get started but would like to monitor how much storage the volume contains so that I can be prepared to upgrade to a larger volume. I can’t seem to see a way to do this with flyctl. Am I missing something?

Also the upgrade process to a larger volume doesn’t look too seamless as I’ll have to create a new volume and provision it to my Fly app, and transfer all files from old volume, instead of just scaling my existing volume, so I’ll just add a big ol’ +1 to that feature as I’ve seen it mentioned a few times in the forum!


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This is harder than it should be! We don’t actually know how much disk space you have free externally, volumes are pretty opaque to us.

The best way to see disk usage is to run fly ssh console -C "du -sh".

You are right that adding a new volume is difficult for Redis apps. Expanding volumes is on our wish list and I think we’ll be doing a bunch of neat volume work in 2-3 months.

Thanks for the temporary solution @kurt !! Really looking forward to those volume upgrades in the coming months <3

It would be great to get volume statistics pushed to prometheus. That way a grafana instance can do alerting!

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Hi! I just wanted to jump in to follow up on this since its been a couple months. The new dashboard is coming along great and I see the new Volumes tab! Is this where I should expect to see Volume management to allow resizing in the future?


Looks like you can query the volume’s stats with the fly_volume_used_pct metric (docs), but if you want to figure out how much of the volume is free, you’re better off using the metrics from fly_instance_filesystem* (docs). That’s what Fly does to show your app’s volume usage in their hosted Grafana.

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