On 3/1/21 10:42 AM, Fabian Ebner wrote:
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.eb...@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.


Could it make sense to just set the block size equal to the image size with count=1 ? Since the images will always be very small anyway...

  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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