There's no concerns from my PoV

@ravanelli Do we have any numbers on the size of the metadata that will be fetched from LVFS?

Given that IoT devices can be resource constrained, there is a small concern that repeated fetches of metadata could accumulate on the device and cause ENOSPC problems.

Also, what is the default frequency for metadata fetches and can the frequency be configured?

Hi @miabbott I don't have this kind of info. I will bring/add your concerns to the change and the issue https://github.com/coreos/fedora-coreos-tracker/issues/1512, where we can discuss it with a broad team and collect more info, special from Richard Hughes @rhughes.

there is a small concern that repeated fetches of metadata could accumulate on the device

Newer metadata replaces older metadata when the signature has been verified:

[hughsie@hughsie-work ~]$ du -h /var/lib/fwupd/metadata/lvfs/* /var/cache/fwupd/
936K /var/lib/fwupd/metadata/lvfs/metadata.xml.xz
4.0K /var/lib/fwupd/metadata/lvfs/metadata.xml.xz.jcat
4.0K /var/cache/fwupd/motd.d
7.3M /var/cache/fwupd/

Also, what is the default frequency for metadata fetches and can the frequency be configured?

It's triggered once per hour, but it only downloads metadata every 24h. The 1h is configured in fwupd-refresh.timer -- does that help?

It's triggered once per hour, but it only downloads metadata every 24h. The 1h is configured in fwupd-refresh.timer -- does that help?

Hey @rhughes - does it also only download things if something has changed?

For example if nothing changed I'm hoping it doesn't re-download everything.

For example if nothing changed I'm hoping it doesn't re-download everything.

Correct -- we download the tiny .jcat file first, and if that's changed then we do the .xml.xz file.

It's triggered once per hour, but it only downloads metadata every 24h. The 1h is configured in fwupd-refresh.timer -- does that help?

Probably don't need it hourly TBH but that's minor detail.

Probably don't need it hourly TBH but that's minor detail.

I think the logic was that if you only powered on the machine for 4 hours a day and you didn't hit that exact cron time you'd never get new metadata. The hourly action just forces fwupd to recalculate the metadata age again, so in 23 of the 24 cases you get:

$ fwupdmgr refresh 
Firmware metadata last refresh: 1 hour ago. Use --force to refresh again.

...and no data gets downloaded. Every 24h we download the 4kB .jcat file, and if that's changed we download the ~1MB .xml.xz file -- which happens nearly every day at the moment as so many updates are being pushed to the LVFS. I've opened https://github.com/fwupd/fwupd/pull/6001 as 1MB/day might be expensive for some hardware, both in terms of bandwidth and $$$.

(Apparently commenting on an issue doesn't subscribe you to it, so I missed the conversation until now...)

Thanks for the additional info @rhughes !

It seems unlikely that the size of the metadata on disk would be an issue and I appreciate the PR to help adjust the frequency of metadata fetches.

The original OK from @pbrobinson still stands, IMO. :smile:

Change in https://src.fedoraproject.org/rpms/fedora-release/pull-request/279