+ my $pv = PVE::Storage::LVMPlugin::lvm_pv_info($dev);
+ # keep some free space just in case
+ my $datasize = $pv->{size} - 128*1024;
+ # default to 1% for metadata
+ my $metadatasize = $datasize/100;
+ # but at least 1G, as recommended in lvmthin man
+ $metadatasize = 1024*1024 if $metadatasize < 1024*1024;
+ # but at most 16G, which is the current lvm max
+ $metadatasize = 16*1024*1024 if $metadatasize > 16*1024*1024;
+ # shrink data by needed amount for metadata
+ $datasize -= 2*$metadatasize;