etcfsctl

etcfsctl is the operator's command-line tool. It connects directly to etcd, with no EtcFS daemon involved, and runs the code in pkg/fsck, pkg/fsinfo, pkg/membership, pkg/arena and pkg/fencing.

etcfuse-meta also has --fsck and --info flags, but using them means starting the daemon that mounts the filesystem. etcfsctl can check a cluster without mounting anything.

etcfsctl [flags] <command> [args]

Commands

Command	Does
status	Filesystem-wide statistics: inodes, extents, arenas, members.
members	List cluster members.
arenas	List arena ownership and utilization.
fsck	Run the offline filesystem checker.
scrub	Run one scrub pass and report anomalies.
fence <node-id>	Record a fence intent for a departed node.
quota	Report usage against every quota root. Advisory: see below.
quota set <ino> --bytes=N --inodes=N	Make a directory a quota root. Advisory: see below.
quota clear <ino>	Remove a quota root.

Quotas are advisory

A quota records a limit, and etcfsctl quota reports usage against it. No write or create is rejected for exceeding a limit, so a directory tree can grow past its quota until someone runs the report. The reported usage is as of the moment the report ran.

Quotas are not enforced because an inode does not record its parent directory. Charging each write to its quota root as it happens would need one of two things:

• a parent pointer on every inode, which is a second record to keep consistent with the directory entries;
• an extra Raft round trip in the transaction that publishes each write.

Writes are already limited by their round trips, and a quota is a policy limit, so neither cost is paid. See Metadata Schema.

quota set and quota both print a note that the limit is not enforced.

Flags

Flags go before the command. flag.Parse stops at the first positional argument, so everything after the subcommand is passed to it unparsed, except --json:

Flag	Default	Notes
--etcd-endpoints	http://localhost:2379	Comma-separated.
--etcd-cert, --etcd-key, --etcd-ca	unset	etcd client TLS.
--timeout	10s	Limits how long one command waits on etcd; without it, a partitioned cluster would hang the command.
--json	false	Print JSON. Accepted anywhere on the line, because it is removed from the arguments before the subcommand parses them: etcfsctl status --json and etcfsctl quota set 10 --json --bytes=5 both work.

Examples

etcfsctl --etcd-endpoints=http://10.0.1.4:2379,http://10.0.1.5:2379,http://10.0.1.6:2379 status
etcfsctl members --json | jq .
etcfsctl fence n2                       # after n2's lease has already expired
etcfsctl quota set 4211 --bytes=5368709120
etcfsctl scrub