> Section: [7. Running it](https://jaque.sh/docs/deployment/overview.md) > Next: ui/dashboard > Index: https://jaque.sh/llms.txt Operating jaque reduces to operating its event log. What survives a restart is decided by `-eventlog` alone; what is worth backing up is the log's directory or nothing, depending on the backend; and an upgrade is a binary swap, because every projection rebuilds from the log rather than from a schema that could need migrating. This page states those three rules, the retention flags that bound the log's size, and the three failures people actually hit. ## 1. Durability What survives a restart depends entirely on `-eventlog`. `memory`, the default, keeps the event log in process memory only. A restart loses every event, and the projections (current state, history) rebuild from nothing, not from where they left off. `file://` persists the log to an embedded, on-disk event log store at that path, durable across restarts. `-retain` makes jaque fail fast at startup, instead of running, if `-eventlog` does not guarantee persistence; it is the flag that turns "I meant to configure durability" into a startup error rather than a discovery after the first restart. `nats://` persists to an external, shared event log server, the shared log a multi-engine deployment reads from. ### 1.1 Retention With `file://` or `nats://`, three flags govern how much history the log keeps before compaction drops it. `-eventlog-retain-check-executed` (default `168h`, seven days) is how long `check_executed` events are kept. `-eventlog-retain-state-changed` (default `0`, unbounded) is how long `state_changed` events are kept; `0` is what Nagios-style state history needs. `-eventlog-retain-reachability-changed` (default `0`, unbounded) is how long `reachability_changed` events are kept. `-compaction-interval` (default `1h`) is how often the embedded transport's retention pass runs and drops events past those windows. ## 2. Backing up the event log directory With `-eventlog file://`, the durable state is the on-disk event log directory at ``, and there are two ways to protect it. A cold copy: stop jaque, copy the directory, restart. The directory is not safe to copy while the process is writing to it. Replay: with `-eventlog nats://...` the external event log server holds the durable copy. A fresh jaque instance pointed at the same log replays it from scratch, so there is nothing process-local to back up. ## 3. Upgrades Replace the binary and restart. There is no migration step: the event log format does not change across a binary upgrade, and every projection (current object state, dashboard rows, Livestatus tables) rebuilds by replaying the log from wherever it resumes, from the start for `memory` and from where the log left off for `file://` and `nats://`. In a split deployment, restart each role (`engine`, `worker`, `ui`, `sink`, `notifier`) independently; there is no required ordering between them, because none of them talks to another directly. ## 4. Troubleshooting ICMP checks return `UNKNOWN` with permission denied. The `icmp` check uses unprivileged datagram sockets, which most Linux distributions do not allow by default. Run `sudo sysctl -w net.ipv4.ping_group_range="0 2147483647"`, or a narrower group range. See [Quickstart](https://jaque.sh/docs/get-started/quickstart.md). A passive object keeps going `UNKNOWN`. Check its `freshness_threshold`. Once a result is older than that window the object is forced to `stale_status` (`UNKNOWN` by default) until a fresh result arrives. See [Passive checks](https://jaque.sh/docs/ingest/passive-checks.md). jaque will not start, or a listener will not bind. Another process is already on that port. Check `-listen` (dashboard, API, `/metrics`), `-livestatus-listen` (Livestatus TCP) and `-livestatus-socket` (Livestatus UNIX socket) for a conflicting address or path. ## 5. Security considerations An on-disk event log directory or a remote event log stream is the complete monitoring history, including check output, which often carries hostnames, paths and whatever a plugin printed. A backup of it deserves the same handling as the running process's data. The listeners named in section 4 are unauthenticated; [Security](https://jaque.sh/docs/deployment/security.md) says what that implies.