[systemd-devel] consider dropping defrag of journals on btrfs

[Colin Guthrie]

Phillip Susi wrote on 11/02/2021 16:29:
> 
> Colin Guthrie writes:
> 
>> Are those journal files suffixed with a ~. Only ~ suffixed journals
>> represent a dirty journal file (i.e. from an unexpected shutdown).
> 
> Nope.
> 
>> Journals rotate for other reason too (e.g. user request, overall space
>> requirements etc.) which might explain this wasted space?
> 
> I've made no requests to rotate and config is default, which afaics
> means only rotate when the log hits max size of 128MB.  Thus I wouldn't
> expect to really see any holes in the log, especially in the middle.

I think the defaults are more complex than just "each journal file can 
grow to 128M" no?

I mean there is SystemMaxUse= which defaults to 10% of the partition on 
which journal files live (this is for all journal files, not just the 
SystemMaxFileSize= which refers to just one file).

The default semantics are described in man journald.conf(5)

Again, could be a red herring, so just my first thought.

Col



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