Directory configurations

Every Kudu node requires the specification of directory flags.

The --fs_wal_dir configuration indicates where Kudu will place its write-ahead logs.

The --fs_metadata_dir configuration indicates where Kudu will place metadata for each tablet. It is recommended, although not necessary, that these directories be placed on a high-performance drives with high bandwidth and low latency, e.g. solid-state drives. If --fs_metadata_dir is not specified, metadata will be placed in the directory specified by --fs_wal_dir.

Since a Kudu node cannot tolerate the loss of its WAL or metadata directories, you might want to mirror the drives containing these directories in order to make recovering from a drive failure easier. However, mirroring may increase the latency of Kudu writes.

The --fs_data_dirs configuration indicates where Kudu will write its data blocks. This is a comma-separated list of directories; if multiple values are specified, data will be striped across the directories. If not specified, data blocks will be placed in the directory specified by --fs_wal_dir.

Additionally, --fs_wal_dir and --fs_metadata_dir may be the same as one of the directories listed in --fs_data_dirs, but must not be sub-directories of any of them.