Hard link handling change - which version did it?

[Steffen Grunewald]

Good morning,

since the upgrade instructions aren't completely clear to me, could someone please
fill me in:
Which BeeGFS version 7.4.x made the change(s) to hard-link handling?
The rationale behind the question is that for a limited time we'd need to run a
mix of old (server) and new (client, 7.4.6) versions, and would like to avoid any
issues caused by this.
If the developers tell me "don't mix" I'll have to shut down the whole cluster.

Thanks,
Steffen

--
Steffen Grunewald, Cluster Administrator
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
Am Mühlenberg 1 * D-14476 Potsdam-Golm * Germany
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Fon: +49-331-567 7274
Mail: steffen.grunewald(at)aei.mpg.de
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[vini...@ferrao.net.br]

7.4.3 is when the change was put in effect.

You can check the warning on the link: https://doc.beegfs.io/7.4.6/advanced_topics/upgrade.html

Warning Necessary changes to a message used in metadata hard link creation cause an incompatibility between metadata services >= 7.4.3 and metadata services running versions < 7.4.3. It is therefore necessary to upgrade all metadata nodes in a BeeGFS system to versions >= 7.4.3 at once. Rolling upgrades of metadata services from older versions are not supported. All services other than metadata are not affected by this and can be upgraded in a rolling fashion or used together with other 7.4.x versions.

Regards,

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[Joe McCormick]

One clarification: cross-directory hard links were initially introduced in 7.4.0: https://doc.beegfs.io/7.4.0/release_notes.html#crossdirectoryhardlinks

While mixing minor versions within the BeeGFS 7 release series is never recommended (e.g., 7.3.z and 7.4.z), it is generally safe to temporarily mix patch versions (e.g., 7.4.5 and 7.4.6) during rolling upgrades.

However, as noted by the other poster, BeeGFS 7.4.3 introduced additional changes related to hard links. Because of this, you cannot mix metadata servers running 7.4.3 or newer with those running versions older than 7.4.3 — regardless of whether hard links are in use. If you're currently on version 7.3.x or earlier, I would recommend upgrading directly to 7.4.6.

Note that starting with BeeGFS 8, we are following semantic versioning more strictly to help avoid this kind of confusion going forward: https://doc.beegfs.io/8.0.0/release_notes.html

~Joe