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+# SIGHUP behaviour
+
+## Logger
+
+Logger level can be reloaded with a SIGHUP.
+
+## Storage engine
+
+Shards can be added, removed or reloaded with SIGHUP.
+Each shard from the configuration is matched with existing shards by
+comparing paths from `shard.blobstor` section. After this we have 3 sets:
+
+1. Shards that are missing from the configuration (or have `mode: disabled`) but are currently open.
+   These are closed.
+2. Shards that are added. These are opened and initialized.
+3. Shards that remain in the configuration.
+   For these shards we apply reload to a `metabase` only. If `resync_metabase` is true, the metabase is also resynchronized.
+
+### Metabase
+
+| Changed section | Actions                                                                                                              |
+|-----------------|----------------------------------------------------------------------------------------------------------------------|
+| `path`          | If `path` is different, metabase is closed and opened with a new path. All other configuration will also be updated. |