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blockdev: add set write threshold

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blockdev: set write threshold
This commit is contained in:
Tiago Sousa 2025-08-02 16:58:53 +01:00
parent 1d1e4aa3a7
commit 88d7de0720
2 changed files with 75 additions and 0 deletions
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20
src/PVE/QemuServer.pm
View file

@ -5822,6 +5822,26 @@ sub vm_start_nolock {
warn $@ if $@;
}
# set write threshold for LVM thin provisioning disks
PVE::QemuConfig->foreach_volume(
$conf,
sub {
my ($ds, $drive) = @_;
return if PVE::QemuServer::drive_is_cdrom($drive, 1);
if ($drive->{file} ne 'none') {
my $extra_blockdev_options = {};
# $extra_blockdev_options->{'live-restore'} = $live_restore if $live_restore;
# extra protection for templates, but SATA and IDE don't support it..
$extra_blockdev_options->{'read-only'} = 1
if drive_is_read_only($conf, $drive);
PVE::QemuServer::Blockdev::set_write_threshold(
$storecfg, $vmid, $drive, $extra_blockdev_options,
);
}
},
);
#start nbd server for storage migration
if (my $nbd = $migrate_opts->{nbd}) {

55
src/PVE/QemuServer/Blockdev.pm
View file

@ -820,6 +820,59 @@ sub set_io_throttle {
}
}
sub block_set_write_threshold {
my ($vmid, $nodename, $threshold) = @_;
print "set threshold $nodename $threshold\n";
PVE::QemuServer::mon_cmd(
$vmid,
"block-set-write-threshold",
'node-name' => $nodename,
'write-threshold' => int($threshold),
);
}
sub compute_write_threshold {
my ($storecfg, $volid) = @_;
my $lv_size = PVE::Storage::volume_size_info($storecfg, $volid, 5);
# FIX: change these vars to config inputs
my $chunksize = 1024 * 1024 * 1024; # 1 GiB
my $alert_chunk_percentage = 0.5; # alert when percetage of chunk used
my $write_threshold = $lv_size - $chunksize * (1 - $alert_chunk_percentage);
return $write_threshold;
}
sub set_write_threshold {
my ($storecfg, $vmid, $drive, $options) = @_;
my $volid = $drive->{'file'};
my ($storeid) = PVE::Storage::parse_volume_id($volid);
my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
my $support_qemu_snapshots = PVE::Storage::volume_qemu_snapshot_method($storecfg, $volid);
# set write threshold is only supported for lvm storage using
# qcow2+external snapshots
return if $scfg->{type} ne 'lvm' || $support_qemu_snapshots ne 'mixed';
print "setting threshold for $volid from $storeid\n";
my $snapshots = PVE::Storage::volume_snapshot_info($storecfg, $volid);
my $parentid = $snapshots->{'current'}->{parent};
# for now only set write_threshold for volumes that have snapshots
if ($parentid) {
my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive);
my $nodename = get_node_name('file', $drive_id, $volid, $options);
my $write_threshold = compute_write_threshold($storecfg, $volid);
block_set_write_threshold($vmid, $nodename, $write_threshold);
}
}
sub blockdev_external_snapshot {
my ($storecfg, $vmid, $machine_version, $deviceid, $drive, $snap, $parent_snap) = @_;
@ -868,6 +921,8 @@ sub blockdev_external_snapshot {
node => $snap_fmt_blockdev->{'node-name'},
overlay => $new_fmt_blockdev->{'node-name'},
);
set_write_threshold($storecfg, $vmid, $drive);
}
sub blockdev_delete {