Tune write cache FSTree depth #1521

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opened 2025-12-28 17:35:42 +00:00 by sami · 0 comments

sami commented

2025-12-28 17:35:42 +00:00

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Originally created by @roman-khimov on GitHub (Oct 13, 2025).

I'm always frustrated when we have too many objects in FSTree directories. We use depth: 1 in write cache FSTree for some time, the presumption was that it never has too many objects, while in fact it can if we're pushing small ones. 1G cache for 1K objects is 1M objects or 20K per dir. Larger caches are also possible, 10-100G are all fine.

Describe the solution you'd like

Switch to FSTree depth 2 for write cache, migrate.

Describe alternatives you've considered

Switch to 3, but this seems to add too much overhead for more common case of 1-10M objects when we have 1-10K of them in the cache.

Additional context

#2337

Originally created by @roman-khimov on GitHub (Oct 13, 2025). ## Is your feature request related to a problem? Please describe. I'm always frustrated when we have too many objects in FSTree directories. We use `depth: 1` in write cache FSTree for some time, the presumption was that it never has too many objects, while in fact it can if we're pushing small ones. 1G cache for 1K objects is 1M objects or 20K per dir. Larger caches are also possible, 10-100G are all fine. ## Describe the solution you'd like Switch to FSTree depth 2 for write cache, migrate. ## Describe alternatives you've considered Switch to 3, but this seems to add too much overhead for more common case of 1-10M objects when we have 1-10K of them in the cache. ## Additional context #2337