On Tue, Jul 31, 2012 at 08:18:42AM +0100, luvar@xxxxxxxxxxxx wrote: > usb 2-4.4: USB disconnect, device number 10 So what's this? Is this at all related to how you've created your RAID device? You haven't told us what your RAID device on dm-3 is composed of (i.e., what are the underlying devices). And there were no OOPS or BUG or WARN messages in your dmesg? > PS: Writing to disk from jbd2/dm-3-8 still active (iotop shows it still on top of I/O activity). I'm not sure if your kernel has trace debugging enabled, or if you have debugfs mounted, but try this: echo 1 > /sys/kernel/debug/tracing/events/jbd2/jbd2_run_stats/enable cat /sys/kernel/debug/tracing/trace_pipe If these commands don't work try running this command and see if it works then: mount -t debugfs debugfs /sys/kernel/debug Let us know if you see jbd2 activity. It's possible that sync isn't returning because some process is still writing to the file system, and if I recall correctly, Linux 3.2 didn't have some of the sync livelock fixes that could cause sync to not return until the file system had actually quieted down completely. Regards, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html