WIP, rewrite in Python

cfg/config.ini

@@ -0,0 +1,32 @@
+[main]
+# Openssl password file (first line is the password).
+keyfile = /etc/btv/key
+
+[subvol]
+# Directory containing all subvolumes.
+dir = /mnt/pool/subvol
+
+# Prefix of subvolumes that should be ignored.
+ignore_prefix = _
+
+[snap]
+# Directory to place local snapshots in.
+dir = /mnt/pool/snap
+
+# Every x-th snapshot is promoted to Rank 1 so it gets to stay around longer.
+# Default is 6, i.e. once per hour assuming 10-minute service timer.
+rank_1_interval=6
+
+# Every x-th snapshot is promoted to Rank 2 so it is serialized to storage.
+# Default is 24, i.e. every 4 hours provided the assumption in the previous
+# comment holds.
+rank_2_interval=24
+
+[prune]
+# How many snapshots of each Rank to keep around.
+# Note: pruning is only performed when a new Rank 2 snapshot is created.
+# Default values are 25, 36, and 42, i.e. 5 hours for Rank 0, 2 days for Rank 1,
+# and a week for Rank 2.
+rank_0_count=25
+rank_1_count=36
+rank_2_count=42