From 1abbe93de3c6d0962839aeb69b4f6a3a1b85f814 Mon Sep 17 00:00:00 2001
From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Sat, 5 Dec 2020 10:06:21 +1100
Subject: [PATCH 1/1] initial setup

---
 sss.sh | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100755 sss.sh

diff --git a/sss.sh b/sss.sh
new file mode 100755
index 0000000..d1c581c
--- /dev/null
+++ b/sss.sh
@@ -0,0 +1,92 @@
+#!/bin/bash
+#
+# Snapshot Snapping Scheme
+#
+# This is a cron bot to manage the snapshots of an nilfs2 file system,
+# so as to preserve 7 most recent daily, 4 most recent weekly and 12
+# most recent monthly snapshots, in addition to labelled ones.
+#
+# The cron bot is expected to run once an hour
+
+# hourly = every hour
+# daily = .. keep one of the hourly yesterday
+# weekly = .. keep one of the daily last week
+# monthly = .. keep one of the daily last month
+
+DEV=/dev/sda5
+KEEPHH=12
+KEEPDD=15
+
+FIVELY="$(date -d '-5 minutes' '+%Y-%m-%d %H:%M:%S')"
+HOURLY="$(date -d '-1 hour' '+%Y-%m-%d %H:%M:%S')"
+DAILY="$(date -d '-1 days' '+%Y-%m-%d %H:%M:%S')"
+MONTHLY="$(date -d '-1 months' '+%Y-%m-%d %H:%M:%S')"
+WEEKLY="$(date -d '-7 days' '+%Y-%m-%d %H:%M:%S')"
+YEARLY="$(date -d '-1 years' '+%Y-%m-%d %H:%M:%S')"
+
+date "+%Y-%m-%d %H:%M:%S ---- checking" >&2
+lscp -s | while read CNO DATE TIME REST ; do
+    TS="$DATE $TIME"
+    [ "$CNO" = "CNO" ] && continue
+    if [[ "$TS" < "$YEARLY" ]] ; then
+	if [ "$KEEPYY" = "${DATE:0:4}" ] ; then
+	    echo "# discard year duplicate $CNO $DATE $TIME" >&2
+	    chcp cp $CNO
+	else
+	    KEEPYY="${DATE:0:4}"
+	fi
+	echo "# keep first of year $CNO $DATE $TIME" >&2
+	continue
+    fi
+    # Within last year
+    if [[ "$TS" < "$MONTHLY" ]] ; then
+	if [ "$KEEPMM" = "${DATE:0:7}" ] ; then
+	    echo "# discard month duplicate $CNO $DATE $TIME" >&2
+	    chcp cp $CNO
+	else
+	    KEEPMM="${DATE:0:7}"
+	fi
+    fi
+    # Within last month
+    if [[ "$TS" < "$WEEKLY" ]] ; then
+	if [[ "$KEEPDD" = "${DATE:8:2}" ]] ; then
+	    if [ -z "$KEEPWW" ] ; then
+		KEEPWW="${DATE:8:2}"
+		continue
+	    fi
+	    echo "# discard duplicate day $KEEPDD: $CNO $DATE $TIME" >&2
+	else 
+	    echo "# discard not day $KEEPDD: $CNO $DATE $TIME" >&2
+	fi
+	chcp cp $CNO
+	continue
+    fi
+    # Within last week
+    if [[ "$TS" < "$DAILY" ]] ; then
+	[[ "$KEEPHH" = "${TIME:0:2}" ]] && continue
+	echo "# discard not hour $KEEPHH: $CNO $DATE $TIME" >&2
+	chcp cp $CNO
+	continue
+    fi
+    # Within last day
+    if [[ "$TS" < "$HOURLY" ]] ; then
+	if [ "$KEEP55" = "${TIME:0:2}" ] ; then
+	    echo "# discard duplicate for hour $KEEP55: $CNO $DATE $TIME" >&2
+	    chcp cp $CNO
+	else
+	    KEEP55="${TIME:0:2}"
+	    #echo "# keep first of hour $KEEP55: $CNO $DATE $TIME" >&2
+	fi
+	continue
+    fi
+    # Within last hour
+    #echo "# keep within last hour $CNO $DATE $TIME" >&2
+    [[ "$TS" < "$FIVELY" ]] && continue
+    echo "$CNO $DATE $TIME is within last five minutes"
+    #echo "# $CNO is within last five minutes " >&2
+done | if read X ; then
+    :
+else
+    date "+# new snapshot at %Y-%m-%d %H:%M:%S" >&2
+    mkcp -s $DEV
+fi
-- 
2.39.2