app-metrics/collectd[udev] should install the udev rule from "contrib/99-storage-collectd.rules" for the disk plugin to have usable udev attribute for this plugin "UdevNameAttr" option. This option is required to make sure that the same disk always ends in the same RRD file no matter which particular device node it ends being assigned by the OS. However, using the most fitting ID_SERIAL udev attribute for this purpose results in data about the whole disk and each partition being mixed together incorrectly, since this attribute has exactly the same value for the whole disk device node and its particular partition nodes. That's why a new ID_COLLECTD udev attribute is needed, which differentiates between the whole disk and its particular partitions. This is provided by the aforementioned udev rule file, which should be installed.
I am a little bit undecided. We have USE=contrib which will allow you to manually install the file when needed.
Why I am undecided: 1) It's just USE=collectd_plugins_disk which can make use of it when compiled with USE=udev. 2) If you have a problem with changing device names, I think your solution to just address the problem for collectd is wrong. I.e. I think the correct solution would be to write an udev rule for all your disks to ensure persistent names. That way you would tackle the problem in general. 3) So this will become a very specific problem. I.e. you don't care about non-persistent disk names in general but in collectd because of wrong stats. So I tend to say, "in this specific case, set USE=contrib and install the rule on your own" ...but in the end we are also just talking about a simple UDEV rule which will add just additional attributes (useless for most users and everyone who will address the problem in general but it's also just an attribute).
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=2f41c6647286fb4c39a56753b255cc7ce802bb52 commit 2f41c6647286fb4c39a56753b255cc7ce802bb52 Author: Thomas Deutschmann <whissi@gentoo.org> AuthorDate: 2021-02-05 17:04:17 +0000 Commit: Thomas Deutschmann <whissi@gentoo.org> CommitDate: 2021-02-05 18:09:13 +0000 app-metrics/collectd: rev bump - Migrate to EAPI 7. - Migrate to LUA eclass. [Bug 752558] - Migrate to acct-* eclass. [Bug 701254] - Install UDEV rule when USE=collectd_plugins_disk with USE=udev. [Bug 763090] Bug: https://bugs.gentoo.org/701254 Closes: https://bugs.gentoo.org/752558 Closes: https://bugs.gentoo.org/763090 Package-Manager: Portage-3.0.14, Repoman-3.0.2 Signed-off-by: Thomas Deutschmann <whissi@gentoo.org> app-metrics/collectd/collectd-5.12.0-r1.ebuild | 568 +++++++++++++++++++++++++ 1 file changed, 568 insertions(+)
Thanks Thomas. I agree a system-wide solution would be better, however that's the best thing we have at hand at this moment. This solution also benefits from being documented in collectd.conf(5). (To be fair I am bit biased here, since it is me who added this ruleset upstream, but based on something that others were already using). Anyway, it's great that the rule will now be managed by portage so it will update or uninstall automatically together with the app-metrics/collectd package, rather than an user having to remember to do it manually.
