On Sat, 19 Feb 2011 00:47:10 +0000 Mathias Burén <mathias.buren@xxxxxxxxx> wrote: > Hi, > > >From the mdadm manual: > > "-b, --bitmap= > [...] > Note: external bitmaps are only known to work on ext2 and ext3. > Storing bitmap files on other filesystems may result in serious > problems." > > I was planning to store the external bitmap on an ext4 partition. Will > this be a problem, or is the warning there because it hasn't been > tested enough but no problems found? External bitmaps use 'BMAP' to find where the file lives on the device and then writes directly to the device - not through the filesystem. So as long as there is no tail-packing to block migration happening it should work fine. I haven't looked inside ext4 but I am fairly confident that external bitmaps will work properly. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
