[pve-devel] [PATCH qemu-server] fix #3324: clone disk: use larger blocksize for EFI disk when possible
Fabian Ebner
f.ebner at proxmox.com
Mon Mar 1 11:23:55 CET 2021
After a short off-list discussion with Thomas, we decided to first
assert that the size is a multiple of 1024 and then simply use bs=1024.
If a new architecture with a strange-sized VARS file comes along we have
to adapt it though.
Am 01.03.21 um 10:42 schrieb Fabian Ebner:
> Moving to Ceph is very slow when bs=1. Instead, use the biggest possible power
> of two <= 1024. At the moment our EFI image sizes are multiples of 1024, so
> just using 1024 wouldn't be a problem, but this feels more future-proof.
>
> Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
> ---
>
> I did not see an way for 'qemu-img dd' to use a larger blocksize while still
> specifying the exact total size if it is not a multiple of the blocksize.
>
> PVE/QemuServer.pm | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index f401baf..e579cdf 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -6991,7 +6991,15 @@ sub clone_disk {
> # that is given by the OVMF_VARS.fd
> my $src_path = PVE::Storage::path($storecfg, $drive->{file});
> my $dst_path = PVE::Storage::path($storecfg, $newvolid);
> - run_command(['qemu-img', 'dd', '-n', '-O', $dst_format, "bs=1", "count=$size",
> +
> + # Ceph doesn't like too small blocksize, see bug #3324
> + my $bs = 1;
> + while ($bs < $size && $bs < 1024 && $size % $bs == 0) {
> + $bs *= 2;
> + }
> + my $count = $size / $bs;
> +
> + run_command(['qemu-img', 'dd', '-n', '-O', $dst_format, "bs=$bs", "count=$count",
> "if=$src_path", "of=$dst_path"]);
> } else {
> qemu_img_convert($drive->{file}, $newvolid, $size, $snapname, $sparseinit);
>
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