Post #3921871
2026-07-18 19:44 UTC
Tune LMDB, Entry Cache and DN Cache in 389 Directory Server
Tune 389 Directory Server LMDB map size, entry cache, DN cache, and normalized DN cache using dsconf backend config, monitor dbmon, and memory budgeting on MDB backends.
https://www.golinuxcloud.com/389-directory-server-lmdb-tuning/
SMH. I wrote #LMDB so that we could eliminate the entry and DN caches in OpenLDAP. Once again, the 389DS guys are Doing It Wrong. They've perpetuated the cache tuning headaches of BDB instead of properly leveraging LMDB.
Replies (1)
-
@hyc@mastodon.social 2026-07-18 19:54
The entry and DN caches will churn a lot during any normal workload, which leads to heap fragmentation, which will cause server performance to degrade the longer it runs. That's why I went to such pains to ensure zero mallocs in LMDB's read path, so it's possible to service an LDAP query with zero heap use, and thus zero chance of heap fragmentation issues. Apparently issues they just didn't think about. http://highlandsun.com/hyc/malloc/