Running MythTV on XFS? Noticed that all your recordings end up rather fragmented? (use xfs_bmap to find out) Well, the culprit is MythTV not being too nice to the file system. Good news is, it’s rather fixable.

From the MythTV source code, edit libs/libmythtv/ThreadedFileWrite.cpp and look for the following:

void ThreadedFileWriter::Sync(void)
{
if (fd >= 0)
{
#ifdef HAVE_FDATASYNC
fdatasync(fd);
#else
fsync(fd);
#endif
}
}
You then want to, after the first squiggly bracket (a { ) put in a “return;” so that it looks like this:

void ThreadedFileWriter::Sync(void)
{
return;
if (fd >= 0)
{
#ifdef HAVE_FDATASYNC
fdatasync(fd);
#else
fsync(fd);
#endif
}
}

Recompile MythTV and go!

(Before anybody says, yes – this patch could be neater and all that… I just haven’t had time yet).