jbd2/dm-0-8 consuming all I/O

What is jbd2/dm-0-8 and why It is consuming all my I/O usage and causing I/O wait?

Is there anyway to disable this?

Bonnie++ results: http://pastebin.com/iQCWP1qp

$ sudo hdparm -t /dev/sda1

/dev/sda1:
 Timing buffered disk reads: 108 MB in  3.02 seconds =  35.71 MB/sec

Solution 1:

jbd is the "journaling block device". dm-0-08 indicates a device mapped by device mapper. It just indicates that you are doing IO and it is being flushed out to disk properly. It is not by itself a source of IO.

Here is vague advice based on the vagueness of the question: If you need less iowait time, your machine needs to do less work, work more efficiently, or have more io resources to do work with.

Solution 2:

Was the filesystem recently created? Is there any process named ext4lazyinit?

Then just wait as it inits (prepares, formats) the filesystem.