storage: bitmap detection is incorrect for MD arrays that use journaling #20381
Comments
clockfort
changed the title
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@mvollmer can you take a look? |
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Thanks! Let's see if UDisks2 can give us information about the journal. |
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@clockfort, do you think we should add journal support to Cockpit in general? Would you be able to help? |
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I'd be happy with just enough logic so that it doesn't show up as a warning. Honestly, I think it's only quite rarely used outside of probably Meta's datacenters. It is kind of strictly better than bitmaps, and maybe the reason why people don't use it is that high-level tooling like cockpit doesn't support it 😄 If cockpit is interested in fuller support, yes, I could help out, but all I really want is to not have to mentally gloss over cockpit warning flags on some of my servers. |
A mdraid can have different consistency policies, and "bitmap" is only one of them. We should only tell people to add a bitmap when the policy is "resync". UDisks2 and Cockpit don't understand consistency policy at all, so we do the bare minimum here to detect a journal. Fixes cockpit-project#20381
Yes, that needs to be fixed quickly -> #20404
Absolutely. UDisks2 and Cockpit seemed to have missed the whole consistency policy thing. MDRaid support is very old and a bit neglected, I am afraid. I think we should at least expose the consistency policy in the UDisks2 API, and disable the "Remove" action for journal disks. That kind of thing. It would be great if you could help us find the right balance there. |
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@clockfort, fyi, I have started hacking on UDisks2 a bit: storaged-project/udisks#1274, feel free to join in! :-) |
A mdraid can have different consistency policies, and "bitmap" is only one of them. We should only tell people to add a bitmap when the policy is "resync". UDisks2 and Cockpit don't understand consistency policy at all, so we do the bare minimum here to detect a journal. Fixes cockpit-project#20381
A mdraid can have different consistency policies, and "bitmap" is only one of them. We should only tell people to add a bitmap when the policy is "resync". UDisks2 will have a ConsistencyPolicy property soonish, and we approximate its value until then. Fixes cockpit-project#20381
A mdraid can have different consistency policies, and "bitmap" is only one of them. We should only tell people to add a bitmap when the policy is "resync". UDisks2 will have a ConsistencyPolicy property soonish, and we approximate its value until then. Fixes #20381
Explain what happens
MD arrays that use write journaling ( https://www.kernel.org/doc/Documentation/md/raid5-cache.txt for a brief introduction, if one is unfamiliar) rather than write-intent bitmaps should not receive this warning. The warning for such users is both misleading and isn't even actionable, as bitmaps and journals are mutually exclusive concepts in MD.
Version of Cockpit
315
Where is the problem in Cockpit?
Storage
Server operating system
Fedora
Server operating system version
40
Extra Info
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