--- Begin Message ---
and use it for plugin linked clone
This also enable extended_l2=on, as it's mandatory for backing file
preallocation.
Preallocation was missing previously, so it should increase performance
for linked clone now (around x5 in randwrite 4k)
cluster_size is set to 128k, as it reduce qcow2 overhead (reduce disk,
but also memory needed to cache metadatas)
l2_extended is not enabled yet on base image, but it could help too
to reduce overhead without impacting performance
bench on 100G qcow2 file:
fio --filename=/dev/sdb --direct=1 --rw=randwrite --bs=4k --iodepth=32
--ioengine=libaio --name=test
fio --filename=/dev/sdb --direct=1 --rw=randread --bs=4k --iodepth=32
--ioengine=libaio --name=test
base image:
randwrite 4k: prealloc=metadata, l2_extended=off, cluster_size=64k: 20215
randread 4k: prealloc=metadata, l2_extended=off, cluster_size=64k: 22219
randwrite 4k: prealloc=metadata, l2_extended=on, cluster_size=64k: 20217
randread 4k: prealloc=metadata, l2_extended=on, cluster_size=64k: 21742
randwrite 4k: prealloc=metadata, l2_extended=on, cluster_size=128k: 21599
randread 4k: prealloc=metadata, l2_extended=on, cluster_size=128k: 22037
clone image with backing file:
randwrite 4k: prealloc=metadata, l2_extended=off, cluster_size=64k: 3912
randread 4k: prealloc=metadata, l2_extended=off, cluster_size=64k: 21476
randwrite 4k: prealloc=metadata, l2_extended=on, cluster_size=64k: 20563
randread 4k: prealloc=metadata, l2_extended=on, cluster_size=64k: 22265
randwrite 4k: prealloc=metadata, l2_extended=on, cluster_size=128k: 18016
randread 4k: prealloc=metadata, l2_extended=on, cluster_size=128k: 21611
Signed-off-by: Alexandre Derumier <alexandre.derum...@groupe-cyllene.com>
---
src/PVE/Storage/Common.pm | 27 +++++++++++++++++++++++++++
src/PVE/Storage/Plugin.pm | 5 +----
2 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/src/PVE/Storage/Common.pm b/src/PVE/Storage/Common.pm
index 4e4ad30..8910988 100644
--- a/src/PVE/Storage/Common.pm
+++ b/src/PVE/Storage/Common.pm
@@ -25,6 +25,10 @@ my $RAW_PREALLOCATION = {
full => 1,
};
+my $QCOW2_CLUSTERS = {
+ backed => ['extended_l2=on','cluster_size=128k']
+};
+
=pod
=head1 NAME
@@ -179,4 +183,27 @@ sub qemu_img_create {
run_command($cmd, errmsg => "unable to create image");
}
+=pod
+
+=head3 qemu_img_create_qcow2_backed
+
+ qemu_img_create_qcow2_backed($scfg, $path, $backing_path, $backing_format)
+
+Create a new qemu qcow2 image C<$path> using an existing backing image
C<$backing_path> with backing_format C<$backing_format>.
+
+=cut
+
+sub qemu_img_create_qcow2_backed {
+ my ($scfg, $path, $backing_path, $backing_format) = @_;
+
+ my $cmd = ['/usr/bin/qemu-img', 'create', '-F', $backing_format, '-b',
$backing_path, '-f', 'qcow2', $path];
+
+ my $options = $QCOW2_CLUSTERS->{backed};
+
+ push @$options, preallocation_cmd_option($scfg, 'qcow2');
+ push @$cmd, '-o', join(',', @$options) if @$options > 0;
+
+ run_command($cmd, errmsg => "unable to create image");
+}
+
1;
diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
index 90627b2..8bf4ed3 100644
--- a/src/PVE/Storage/Plugin.pm
+++ b/src/PVE/Storage/Plugin.pm
@@ -847,10 +847,7 @@ sub clone_image {
eval {
local $CWD = $imagedir;
- my $cmd = ['/usr/bin/qemu-img', 'create', '-b',
"../$basevmid/$basename",
- '-F', $format, '-f', 'qcow2', $path];
-
- run_command($cmd);
+ PVE::Storage::Common::qemu_img_create_qcow2_backed($scfg, $path,
"../$basevmid/$basename", $format);
};
my $err = $@;
--
2.39.5
--- End Message ---
