storage_migrate: use bs=4k to copy images with dd

The default block size is 512 bytes, and is quite slow. We do not
want to use blocks bigger than 4k, because we want to detect empty
blocks (sparse).

diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index a904f4ec84fe18f0191f501dc9d2707815a261a7..71b699c7ce725950a5cb53e3b57e6924a2495ee3 100755 (executable)
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -613,11 +613,11 @@ sub storage_migrate {
 
            eval {
                if ($tcfg->{type} eq 'lvmthin') {
-                   run_command([["dd", "if=$src"],["/usr/bin/ssh", "root\@${target_host}",
-                             "dd", 'conv=sparse', "of=$dst"]]);
+                   run_command([["dd", "if=$src", "bs=4k"],["/usr/bin/ssh", "root\@${target_host}",
+                             "dd", 'conv=sparse', "of=$dst", "bs=4k"]]);
                } else {
-                   run_command([["dd", "if=$src"],["/usr/bin/ssh", "root\@${target_host}",
-                             "dd", "of=$dst"]]);
+                   run_command([["dd", "if=$src", "bs=4k"],["/usr/bin/ssh", "root\@${target_host}",
+                             "dd", "of=$dst", "bs=4k"]]);
                }
            };
            if (my $err = $@) {