Timeouts

What each timeout detects

Uploads: [uploads]

[uploads]
idle_timeout_secs = 30
min_rate_bytes_per_sec = 1024   # 1 KiB/s on average; absent or 0: disabled
min_rate_grace_secs = 60

All the keys: Reference [uploads].

The idle timeout

The clock runs only while the server waits for the client. The time the server spends on its storage (slow S3, stalling NFS) never counts.

When the timeout expires, the partial file is dropped (in-flight file deleted, S3 multipart aborted) and nothing is published.

A live upload reaches its file at least every 2 x idle_timeout_secs: the cleanup of leftovers and the takeover of locks rely on it, so give the same value to all instances that share a storage. Raise it for clients that keep a file open without writing (sshfs, a graphical client that asks for a confirmation, a very slow link: at the default, a 32 KiB packet needs ~1.1 KB/s).

The minimum rate

Once min_rate_grace_secs of waiting have passed, an upload must have received on average at least min_rate_bytes_per_sec, like Apache’s RequestReadTimeout ... MinRate. The average runs from the start: a bursty client keeps the credit of its bursts, a trickle is cut at the end of the grace period. The bytes counted are those of accepted WRITE packets, not the offset reached.

Below it, the upload is cut as for idleness. 1 KiB/s cuts a trickle and lets through a 10 KiB/s link that stalls.

TCP keepalive: [tcp_keepalive]

Set on each accepted connection, on the SFTP port and on the HTTP port.

All the keys: Reference [tcp_keepalive].

Network loss in the middle of a transfer: TCP_USER_TIMEOUT

Keepalive probes only a connection with nothing in flight. When the server sends something to a client that is gone (the replies to the WRITE packets of an SFTP upload, a download), TCP_USER_TIMEOUT cuts.

The connection is thus cut 5 s after the upload is abandoned. On Linux, this timeout replaces count: an idle connection whose peer is gone is cut at the first probe that exceeds it (around 70 s on SFTP). It also applies to a client that stops reading: a REST download whose client is suspended is cut at 35 s. A longer network loss (coverage loss, VPN reconnecting) kills the transfer; raise user_timeout_secs if your clients go through such losses.

Outside Linux, nothing is set.

SSH: [sftp]

login_grace_secs and inactivity_timeout_secs cut the connection (0: never); keepalive_interval_secs (0: none) probes the client, keepalive_max (3) cuts after that many probes without an answer. The keys: [sftp].

The answer to an SSH keepalive counts as activity: with a keepalive shorter than inactivity_timeout_secs, a live but idle session is no longer cut for inactivity, only a client that no longer answers is. That is why SSH keepalive is disabled by default.

HTTP: header read timeout

admin.header_read_timeout_secs (10 s, from 1 to 300, CRAFT_FILE_GATE_ADMIN_HEADER_READ_TIMEOUT_SECS) bounds, on the port of the admin API and the file API, the wait for the headers of a request: from the connection, the TLS handshake or the previous response in keep-alive. Beyond it, the connection is closed without a response. It bounds neither a body nor a response.

The port serves only HTTP/1.1; over HTTPS, ALPN offers only http/1.1, and HTTP/2 clients fall back to it.

What you will see