diff --git a/TUNING.md b/TUNING.md index 786c11c..feae9eb 100644 --- a/TUNING.md +++ b/TUNING.md @@ -47,7 +47,9 @@ Construct probes information about block devices using `sysfs(5)`. It must acqui - Review device information with the console command `fs dev`. If detected device information is incorrect or absent, manually configure the appropriate queue depth with the environment variable `ircd_fs_aio_max_events` before execution. - **RocksDB must support parallel Direct-IO reads.** -Construct takes advantage of features incrementally between RocksDB v5.18 through v6.10.2 (and beyond). Unfortunately many distributions ship with RocksDB v5.17.2 (including Ubuntu 20.04) which lacks several features that maximize performance. When Construct is built with `--with-included-rocksdb` it defaults to v6.6.4 (matching Debian stable) which is recommended if possible. At the time of this writing, parallel Direct-IO reads have only recently landed in the RocksDB master branch and not any tagged release. This feature is significant enough for our workload that we preemptively advise configuring with the next tagged release `--with-included-rocksdb=v6.XX.X` once it is available to maximize peformance. +Construct takes advantage of features incrementally between RocksDB v5.18 through v6.10.2 (and beyond)*. Unfortunately many distributions ship with RocksDB v5.17.2 (including Ubuntu 20.04) which lacks several features that maximize performance. When Construct is built with `--with-included-rocksdb` it defaults to v6.6.4 (matching Debian stable) which is recommended if possible. At the time of this writing, parallel Direct-IO reads have only recently landed in the RocksDB master branch and not any tagged release. This feature is significant enough for our workload that we preemptively advise configuring with the next tagged release `--with-included-rocksdb=v6.XX.X` once it is available to maximize peformance. + + * **RocksDB 6.10.1 and 6.10.2 have a bug and cannot be used.** Please check for 6.10.3 or 6.11, otherwise you must use an older version. ### Optimizing Dynamic Memory