For '-drive', qemu-server sets special cache options for EFI disk
using RBD. In preparation to seamlessly switch to the new '-blockdev'
interface, do the same here. Note that the issue from bug #3329, which
is solved by these cache options, still affects current versions.
With -blockdev, the cache options are split up. While cache.direct and
cache.no-flush can be set in the -blockdev options, cache.writeback is
a front-end property and was intentionally removed from the -blockdev
options by QEMU commit aaa436f998 ("block: Remove cache.writeback from
blockdev-add"). It needs to be configured as the 'write-cache'
property for the ide-hd/scsi-hd/virtio-blk device.
The default is already 'writeback' and no cache mode can be set for an
EFI drive configuration in Proxmox VE currently, so there will not be
a clash.
┌─────────────┬─────────────────┬──────────────┬────────────────┐
│ │ cache.writeback │ cache.direct │ cache.no-flush │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│writeback │ on │ off │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│none │ on │ on │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│writethrough │ off │ off │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│directsync │ off │ on │ off │
├─────────────┼─────────────────┼──────────────┼────────────────┤
│unsafe │ on │ off │ on │
└─────────────┴─────────────────┴──────────────┴────────────────┘
Table from 'man kvm'.
Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---
New in v2.
src/PVE/Storage.pm | 4 ++--
src/PVE/Storage/ISCSIDirectPlugin.pm | 2 +-
src/PVE/Storage/Plugin.pm | 27 +++++++++++++++++++++++++--
src/PVE/Storage/RBDPlugin.pm | 7 ++++++-
src/PVE/Storage/ZFSPlugin.pm | 2 +-
src/PVE/Storage/ZFSPoolPlugin.pm | 2 +-
6 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/src/PVE/Storage.pm b/src/PVE/Storage.pm
index d671080..3b0f07e 100755
--- a/src/PVE/Storage.pm
+++ b/src/PVE/Storage.pm
@@ -712,7 +712,7 @@ sub abs_filesystem_path {
# see the documentation for the plugin method
sub qemu_blockdev_options {
- my ($cfg, $volid) = @_;
+ my ($cfg, $volid, $options) = @_;
my ($storeid, $volname) = parse_volume_id($volid);
@@ -724,7 +724,7 @@ sub qemu_blockdev_options {
die "cannot use volume of type '$vtype' as a QEMU blockdevice\n"
if $vtype ne 'images' && $vtype ne 'iso' && $vtype ne 'import';
- return $plugin->qemu_blockdev_options($scfg, $storeid, $volname);
+ return $plugin->qemu_blockdev_options($scfg, $storeid, $volname, $options);
}
# used as last resort to adapt volnames when migrating
diff --git a/src/PVE/Storage/ISCSIDirectPlugin.pm
b/src/PVE/Storage/ISCSIDirectPlugin.pm
index 4bf6d07..8f25577 100644
--- a/src/PVE/Storage/ISCSIDirectPlugin.pm
+++ b/src/PVE/Storage/ISCSIDirectPlugin.pm
@@ -106,7 +106,7 @@ sub path {
}
sub qemu_blockdev_options {
- my ($class, $scfg, $storeid, $volname) = @_;
+ my ($class, $scfg, $storeid, $volname, $options) = @_;
my $lun = ($class->parse_volname($volname))[1];
diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
index f162a13..7fe1b17 100644
--- a/src/PVE/Storage/Plugin.pm
+++ b/src/PVE/Storage/Plugin.pm
@@ -1884,7 +1884,7 @@ sub rename_volume {
=head3 qemu_blockdev_options
- $blockdev = $plugin->qemu_blockdev_options($scfg, $storeid, $volname)
+ $blockdev = $plugin->qemu_blockdev_options($scfg, $storeid, $volname,
$options)
Returns a hash reference with the basic options needed to open the volume via
QEMU's C<-blockdev>
API. This at least requires a C<< $blockdev->{driver} >> and a reference to
the image, e.g.
@@ -1915,11 +1915,34 @@ The storage ID.
The volume name.
+=item C<$options>
+
+A hash reference with additional options.
+
+=over
+
+=item C<< $options->{hints} >>
+
+A hash reference with hints indicating what the volume will be used for. This
can be safely ignored
+if no concrete issues are known with your plugin. For certain use cases,
setting additional
+(plugin-specific) options might be very beneficial however. An example is
setting the correct cache
+options for an EFI disk on RBD. The list of hints might get expanded in the
future.
+
+=over
+
+=item C<< $options->{hints}->{'efi-disk'} >>
+
+(optional) If set, the volume will be used as the EFI disk of a VM, containing
its OMVF variables.
+
+=back
+
+=back
+
=back
=cut
sub qemu_blockdev_options {
- my ($class, $scfg, $storeid, $volname) = @_;
+ my ($class, $scfg, $storeid, $volname, $options) = @_;
my $blockdev = {};
diff --git a/src/PVE/Storage/RBDPlugin.pm b/src/PVE/Storage/RBDPlugin.pm
index 522d03c..6fa0689 100644
--- a/src/PVE/Storage/RBDPlugin.pm
+++ b/src/PVE/Storage/RBDPlugin.pm
@@ -494,7 +494,7 @@ sub path {
}
sub qemu_blockdev_options {
- my ($class, $scfg, $storeid, $volname) = @_;
+ my ($class, $scfg, $storeid, $volname, $options) = @_;
my $cmd_option = PVE::CephConfig::ceph_connect_option($scfg, $storeid);
my ($name) = ($class->parse_volname($volname))[1];
@@ -532,6 +532,11 @@ sub qemu_blockdev_options {
$blockdev->{'key-value-pairs'}->{keyring} = "$cmd_option->{keyring}";
}
+ # SPI flash does lots of read-modify-write OPs, without writeback this
gets really slow #3329
+ if ($options->{hints}->{'efi-disk'}) {
+ $blockdev->{'key-value-pairs'}->{'rbd-cache-policy'} = 'writeback';
+ }
+
return $blockdev;
}
diff --git a/src/PVE/Storage/ZFSPlugin.pm b/src/PVE/Storage/ZFSPlugin.pm
index 89eff3c..1392781 100644
--- a/src/PVE/Storage/ZFSPlugin.pm
+++ b/src/PVE/Storage/ZFSPlugin.pm
@@ -248,7 +248,7 @@ sub path {
}
sub qemu_blockdev_options {
- my ($class, $scfg, $storeid, $volname) = @_;
+ my ($class, $scfg, $storeid, $volname, $options) = @_;
my $name = ($class->parse_volname($volname))[1];
my $guid = $class->zfs_get_lu_name($scfg, $name);
diff --git a/src/PVE/Storage/ZFSPoolPlugin.pm b/src/PVE/Storage/ZFSPoolPlugin.pm
index 313d45b..302c965 100644
--- a/src/PVE/Storage/ZFSPoolPlugin.pm
+++ b/src/PVE/Storage/ZFSPoolPlugin.pm
@@ -162,7 +162,7 @@ sub path {
}
sub qemu_blockdev_options {
- my ($class, $scfg, $storeid, $volname) = @_;
+ my ($class, $scfg, $storeid, $volname, $options) = @_;
my ($path) = $class->path($scfg, $volname, $storeid);
--
2.39.5
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