The commitlog api originally implied that the commitlog_directory would contain files from a single commitlog instance. This is checked in segment_manager::list_descriptors, if it encounters a file with an unknown prefix, an exception occurs in `commitlog::descriptor::descriptor`, which is logged with the `WARN` level.
A new schema commitlog was added recently, which shares the filesystem directory with the main commitlog. This causes warnings to be emitted on each boot. This patch solves the warnings problem by moving the schema commitlog to a separate directory. In addition, the user can employ the new `schema_commitlog_directory` parameter to move the schema commitlog to another disk drive.
This is expected to be released in 5.3.
As #13134 (raft tables->schema commitlog) is also scheduled for 5.3, and it already requires a clean rolling restart (no cl segments to replay), we don't need to specifically handle upgrade here.
Fixes: #11867Closes#13263
* github.com:scylladb/scylladb:
commitlog: use separate directory for schema commitlog
schema commitlog: fix commitlog_total_space_in_mb initialization
4d6443e030