[pve-devel] [PATCH guest-common v3 09/22] vzdump: schema: add fleecing property string

[Fiona Ebner]

It's a property string, because that avoids having an implicit
"enabled" as part of a 'fleecing-storage' property. And there likely
will be more options in the future, e.g. threshold/limit for the
fleecing image size.

Storage is non-optional, so the storage choice needs to be a conscious
decision. Can allow for a default later, when a good choice can be
made further down the stack. The original idea with "same storage as
VM disk" is not great, because e.g. for LVM, it would require the same
size as the disk up front.

Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 src/PVE/VZDump/Common.pm | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/PVE/VZDump/Common.pm b/src/PVE/VZDump/Common.pm
index 5be87a0..30bd044 100644
--- a/src/PVE/VZDump/Common.pm
+++ b/src/PVE/VZDump/Common.pm
@@ -33,6 +33,7 @@ my $dowhash_to_dow = sub {
 };
 
 our $PROPERTY_STRINGS = {
+    'fleecing' => 'backup-fleecing',
     'performance' => 'backup-performance',
     'prune-backups' => 'prune-backups',
 };
@@ -79,6 +80,24 @@ sub parse_dow {
     return $res;
 };
 
+PVE::JSONSchema::register_format('backup-fleecing', {
+    enabled => {
+	description => "Enable backup fleecing. Cache backup data from blocks where new guest "
+	    ."writes happen on specified storage instead of copying them directly to the backup "
+	    ."target. This can help guest IO performance and even prevent hangs, at the cost of "
+	    ."requiring more storage space.",
+	type => 'boolean',
+	default => 0,
+	optional => 1,
+	default_key => 1,
+    },
+    storage => get_standard_option('pve-storage-id', {
+	description => "Use this storage to storage fleecing images. For efficient space usage, "
+	    ."it's best to use a local storage that supports discard and either thin provisioning "
+	    ."or sparse files.",
+    }),
+});
+
 PVE::JSONSchema::register_format('backup-performance', {
     'max-workers' => {
 	description => "Applies to VMs. Allow up to this many IO workers at the same time.",
@@ -262,6 +281,12 @@ my $confdesc = {
 	format => 'backup-performance',
 	optional => 1,
     },
+    fleecing => {
+	type => 'string',
+	description => "Options for backup fleecing (VM only).",
+	format => 'backup-fleecing',
+	optional => 1,
+    },
     lockwait => {
 	type => 'integer',
 	description => "Maximal time to wait for the global lock (minutes).",
-- 
2.39.2