Update BACKUPS.md

DOC/BACKUPS.md

@@ -1,9 +1,31 @@
 # Backups
 
-rqlite supports hot backing up a node. You can retrieve and write a consistent snapshot of the underlying SQLite database to a file like so:
+rqlite supports hot backing up a node. You can retrieve and write a copy of the underlying SQLite database to a file via the CLI:
+```
+127.0.0.1:4001> .backup bak.sqlite3
+backup file written successfully
+```
+This command will write the SQLite database file to `bak.sqlite3`.
 
+You can also access the rqlite API directly, via a HTTP `GET` request to the endpoint `/db/backup`. For example, using `curl`, and assuming the node is listening on `localhost:4001`, you could retrieve a backup as follows:
 ```bash
-curl localhost:4001/db/backup -o bak.sqlite3
+curl -s -XGET localhost:4001/db/backup -o bak.sqlite3
+```
+
+In either case the generated file file can then be used to restore a node (or cluster) using the [restore API](https://github.com/rqlite/rqlite/blob/master/DOC/RESTORE_FROM_SQLITE.md).
+
+## Generating a SQL text dump
+You can dump the database in SQL text format via the CLI as follows:
 ```
+127.0.0.1:4001> .dump bak.sql
+SQL text file written successfully
+```
+The API can also be accessed directly:
+```bash
+curl -s -XGET localhost:4001/db/backup?fmt=sql -o bak.sql
+```
+
+## Backup isolation level
+The isolation offered by backups is `READ COMMITTED`. This means that any changes due to transactions to the database, that take place during the backup, will be reflected immediately once the transaction is committed, but not before.
 
-This file can then be used to restore a node (or cluster) using the [restore API](https://github.com/rqlite/rqlite/blob/master/DOC/RESTORE_FROM_SQLITE.md).
+See the [SQLite documentation](https://www.sqlite.org/isolation.html) for more details.