snapshots-create: improved tar arguments

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

1 files changed, 28 insertions, 7 deletions

diff --git a/snapshots-create.sh b/snapshots-create.sh
index 8f031f0..9b2cbe7 100755
--- a/snapshots-create.sh
+++ b/snapshots-create.sh
@@ -85,18 +85,39 @@ cd ${TEMP}
 # create the tarball and move it to the right location
 write_time_log "START TARBALL		$(date -u)"
 if [ ! -f "${FILENAME%.bz2}" ]; then
+	# Build a directory of stuff to tar up.
 	rm -rf portage
-	rsync -Wqa "$MASTER"/ portage/
+	rsync -Wqa \
+		"$MASTER"/ \
+		portage/
 	if [ $? -ne 0 ]; then
 		echo "rsync run failed!"
 		exit 1
 	fi
-	tar \
-		--owner=portage \
-		--group=portage \
-		-cf ${FILENAME%.bz2} \
-		portage \
-		--exclude .checksum-test-marker
+
+	TAR_OPTIONS=(
+	# GNU tar format saves approximately 1K per file in the tarball over POSIX
+	# format. Multiply ~170k files, and the savings are large.
+		--format=gnu
+	# Sorting by name produces consistent ordering and helps compression of
+	# related content. Custom ordering might further improve ordering in future
+	# (eg all metadata.xml first)
+		--sort=name
+	# Force ownership of content:
+		--owner=portage
+		--group=portage
+	# Excluded content:
+	# This is handled further up, by not rsyncing them at all!
+	#	--no-wildcards
+	#	--exclude-from "${EXCLUSION_LIST}"
+	# Do not capture any xattr/acl info at all.
+		--no-acls
+		--no-xattrs
+		--no-selinux
+	)
+	tar "${TAR_OPTIONS[@]}" \
+		-cf posix-bf1-${FILENAME%.bz2} \
+		portage
 	rc=$?
 	rm -rf portage
 	if [ $rc -ne 0 ]; then