nats-io/nats-server · error

Error storing entry to WAL: %v

Error message

Error storing entry to WAL: %v

What it means

storeToWAL returned an error other than ErrStoreClosed while an append-entry follower was persisting a received entry. The write error was already recorded via setWriteErrLocked (which may shut the store down); the log surfaces it at the replication path.

Source

Thrown at server/raft.go:4819

		// Setup our state for catching up.
		n.debug("AppendEntry did not match [%d:%d] with [%d:%d]", ae.pterm, ae.pindex, n.pterm, n.pindex)
		inbox := n.createCatchup(ae)
		ar := newAppendEntryResponse(n.pterm, n.pindex, n.id, false)
		n.Unlock()
		n.sendRPC(ae.reply, inbox, ar.encode(arbuf))
		arPool.Put(ar)
		return
	}

CONTINUE:
	// Save to our WAL if we have entries.
	if ae.shouldStore() {
		// Only store if an original which will have sub != nil
		if sub != nil {
			if err := n.storeToWAL(ae); err != nil {
				if err != ErrStoreClosed {
					n.warn("Error storing entry to WAL: %v", err)
				}
				n.Unlock()
				return
			}
			n.cachePendingEntry(ae)
			n.resetInitializing()
		} else {
			// This is a replay on startup so just take the appendEntry version.
			n.pterm = ae.term
			n.pindex = ae.pindex + 1
		}
	}

	// Check to see if we have any related entries to process here.
	for _, e := range ae.entries {
		switch e.Type {
		case EntryLeaderTransfer:
			// Only process these if they are new, so no replays or catchups.

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Inspect the recorded write error (disk full, I/O failure) on this node
2. Free disk space or repair storage, then restart to rejoin via catchup/snapshot
3. Monitor werr-driven shutdowns to catch failing disks early

When it happens

Trigger: Thrown at server/raft.go:4819 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/fbf53a6d144be9c4. Report an issue: GitHub.