Restart does not affect the database. So, generally speaking, data loss will not occur upon reboot.
However, it will also restart your workers, which may interrupt any work currently in progress. This can lead to partially finished work, which may have an undesirable effect, depending on the work. You must design any background jobs so that they can be restarted from scratch if necessary (for example, any interaction with databases in a transaction).
A similar effect is also possible for your speakers - in this case, instead of a partially completed task, this will be a partially completed web request. This very rarely causes a problem.
Deployment, but not necessarily restart will also remove any of the files in a temporary directory ( tmp/and log/).
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