What going on? is the forum bug or @vv75 change answer solution multiple times?
i marked several as solution but it deselected them and i selected again.
happens when the solution button isnt directly below the answer but under āā¦ā menu.
i marked as solution, then looked again tn the [ā¦] and it wasnt marked.
i thought i had connectivity issues when selected previously and selected again.
now checked again under [ā¦] where i marked as solution, and the solution choice is shown as not selected.
confusing bug of the forum engine!
and after a bit of thoughtā¦
if the data logs would be treated as sparse files, then before the compaction operation, the unused data could be discarded WITHIN the file so even more free space can be gained on the filesystem.
devs, waddya think?
Itās not a bug. Only one comment can be a solution.
heeeee.
thanks for telling!
and in the current state of things, SEVERAL people solved the question, each one in some aspectā¦
scratched my head and gave you guys hearts instead. 
It was discussed here on the forum and internally. This idea have more cons than pros, I wouldnāt like to repeat this discussion again, but TL;DR:
- too many nuances between OSesā implementation of āsparseā files and punch holes, too fragile
- we messing with append-only approach and punch holes and filling them => we will have more I/O and latency, because the filesystem will actually do not use these holes efficiently
i meant not to fill them, just to punch before copying filled data to the new datalog chunk.
in hope just to spare a bit more hdd space for the operation.
or maybe even punch them as soon as data is no more needed.
The concern #1 still remain, also the occupied space will not change. And it requires special quirks for each FS+OS combination to use the actual size without a punched hole.
only punching holes when data is not needed, without filling them, can be implemented only/first on systems where this is doable/efficient and does not require support on all of them at once.
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And support many backends in parallel? No, the piecestore backed is planned to be dropped in a favor of hashstore, itās hard to support them in parallel - see how many reverts were recently because of existing piecestore and hashtore in the same time.
nonononono.
i mean only the hashstore.
in the data store chunks (those 1gb in size) just punch holes when that data is no longer needed.
just to have less waste space occupied on the storage.
I asked AI for a better explanation, itās pretty accurate: Google Search
See also this discussion:
well and my idea is to also punch that data as holes.
it wont be longer needed anyway.
which will increase fragmentation in exchange, and losing speed.
well that already depends how much.
and of course depends on the underlying fs.
my personal prior observations were that it used too much space on the fs compared to what the web console reported as used.
thanks for pointing, will read that!
You can increase this option to make it more aggressive (in exchange of a higher I/O pressure and maybe missing some customers):
./storagenode setup --help | sls alive-fraction
--hashstore.compaction.alive-fraction float if the log file is not this alive, compact it
(default 0.25)