Ollama logs show server startup, model loading, GPU detection, cloud status, and request errors that do not always appear in client output. They are the quickest place to separate a bad request from a server-side runtime issue.
Log locations depend on how Ollama is installed. Linux service installs use journalctl, macOS stores app and server logs under ~/.ollama/logs, and Windows stores logs under the user's local app data path.
Use logs as a diagnosis surface, then retest the failing command. A log line without a repeated client check can point to an old event instead of the current problem.
Related: How to manage the Ollama service
Related: How to check Ollama server status
Related: How to check Ollama GPU support
$ journalctl -e -u ollama Jul 07 04:42:10 host ollama[1234]: listening on 127.0.0.1:11434
$ journalctl -fu ollama Jul 07 04:42:13 host ollama[1234]: loaded model gpt-oss:20b
$ ls ~/.ollama/logs app.log server.log
$ explorer %LOCALAPPDATA%\Ollama
Inspect app.log, server.log, and upgrade.log in that folder.
$ curl -s http://localhost:11434/api/version {"version":"0.31.1"}