From e9498669e88ad2507364d8d84e6233664185e79c Mon Sep 17 00:00:00 2001
From: Wojciech Kozlowski <wk@wojciechkozlowski.eu>
Date: Thu, 10 Nov 2022 00:13:15 +0100
Subject: [PATCH] Reduce snapshot and backup numbers

---
 .../etc/sanoid/sanoid-templates.conf          | 34 +++++++++++++++----
 .../usr/local/sbin/restic-volume-data         |  2 +-
 .../backups/00-zfs-snapshots.d/sanoid.yml     |  6 ++--
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/playbooks/filesystem/yggdrasil/etc/sanoid/sanoid-templates.conf b/playbooks/filesystem/yggdrasil/etc/sanoid/sanoid-templates.conf
index b78488b..c33a5d5 100644
--- a/playbooks/filesystem/yggdrasil/etc/sanoid/sanoid-templates.conf
+++ b/playbooks/filesystem/yggdrasil/etc/sanoid/sanoid-templates.conf
@@ -1,7 +1,7 @@
-[template_home]
-        hourly = 0
-
-[template_production]
+# Template for system datasets that are not being backed up anywhere. Snapshots are used to provide
+# option for rollback without having to reinstall entire system. If the hardware crashes or becomes
+# corrupt reinstalling might be smarter given the fact that hardware will likely be different.
+[template_system]
         frequently = 0
         hourly = 36
         daily = 30
@@ -10,12 +10,34 @@
         autosnap = yes
         autoprune = yes
 
+# Template for home directories which will use the system template, but they don't change so fast.
+[template_home]
+        hourly = 0
+
+# Template for datasets with production data. Unlike system datasets, production datasets are
+# expected to be backed up, both to spare local storage as well as a remote location. Therefore,
+# snapshots only serve the purpose of providing snapshots for these backups. Otherwise, don't keep
+# snapshots as they will just take up space. Applications that need their data versioned will be
+# versioning themselves so they only need backups.
+[template_production]
+        frequently = 0
+        hourly = 2
+        daily = 2
+        monthly = 0
+        yearly = 0
+        autosnap = yes
+        autoprune = yes
+
+# Template for backup datasets which also doubles as a hot spare. The assumption is that these
+# backup production datasets. In addition to three months of snapshots, keep 36 hourly snapshots for
+# quick rollback in case of trouble. No monthly snapshots are kept as that would require the
+# production template to produce them.
 [template_backup]
         autoprune = yes
         frequently = 0
-        hourly = 30
+        hourly = 36
         daily = 90
-        monthly = 12
+        monthly = 0
         yearly = 0
 
         ### don't take new snapshots - snapshots on backup
diff --git a/playbooks/filesystem/yggdrasil/usr/local/sbin/restic-volume-data b/playbooks/filesystem/yggdrasil/usr/local/sbin/restic-volume-data
index aa38dc7..118e5c5 100644
--- a/playbooks/filesystem/yggdrasil/usr/local/sbin/restic-volume-data
+++ b/playbooks/filesystem/yggdrasil/usr/local/sbin/restic-volume-data
@@ -58,7 +58,7 @@ if __name__ == "__main__":
             subprocess.run(f"{restic_cmd_base} snapshots || {restic_cmd_base} init",
                            shell=True, check=True)
             subprocess.run(f"{restic_cmd_base} backup .", shell=True, cwd=backup_path, check=True)
-            subprocess.run(f"{restic_cmd_base} forget --prune --keep-daily 90 --keep-monthly 12",
+            subprocess.run(f"{restic_cmd_base} forget --prune --keep-daily 30 --keep-monthly 3",
                            shell=True, check=True)
             subprocess.run(f"{restic_cmd_base} check", shell=True, check=True)
 
diff --git a/playbooks/tasks/backups/00-zfs-snapshots.d/sanoid.yml b/playbooks/tasks/backups/00-zfs-snapshots.d/sanoid.yml
index f54467f..76ab9fb 100644
--- a/playbooks/tasks/backups/00-zfs-snapshots.d/sanoid.yml
+++ b/playbooks/tasks/backups/00-zfs-snapshots.d/sanoid.yml
@@ -7,17 +7,17 @@
     marker: "# {mark} ANSIBLE MANAGED BLOCK SYSTEM #"
     block: |
       [bpool/BOOT]
-              use_template = production
+              use_template = system
               recursive = yes
               process_children_only = yes
 
       [rpool/ROOT]
-              use_template = production
+              use_template = system
               recursive = yes
               process_children_only = yes
 
       [rpool/home]
-              use_template = production,home
+              use_template = system,home
               recursive = yes
               process_children_only = yes