On 08/27/2015 11:29 AM, Eric Blake wrote: > On 08/27/2015 09:17 AM, Peter Maydell wrote: >> I've noticed recently that tests/hd-geo-test.c creates test disk >> images which are 4GB in size, which is a problem if the filesystem >> on the host doesn't support sparse files. In particular, OSX's HFS+ >> doesn't have sparse file support, and Windows probably doesn't either. > > Windows NTFS supports sparse files (minimum hole size of 64k), but it > can be a pain to set up, and while it saves disk space, it may actually > slow your program down. > > [At one point cygwin created sparse files on windows by default, but > because it was demonstrated to hurt performance in dealing with sparse > files, because Windows doesn't handle sparse files efficiently, the > cygwin defaults were switched so that it now requires an explicit opt-in > mount option before even attempting sparse files] > >> Worse, if the test fails an assertion somewhere the test doesn't >> clean up after itself and leaves a 4GB file lying around in /tmp/. >> >> It would be nice if we could skip these tests on filesystems that >> don't have sparse file support... > > Or even where sparse files are supported but not default. >
Does this test *require* the raw format? Use tests/libqos/libqos.c mkqcow2 instead. I'll send a patch. --js
