I've an external 500GB HDD connected to my Laptop which runs Ubuntu 12.04. I've formatted the external drive with one ext4 partition which spans the entire disk.
My problem is that the disk makes noise every second, because writes occur to it. I'm not actively writing any file to the disk or use the disk otherwise. It's just mounted and should be idle.
Using iotop, I can see that with the disk plugged in, some jbd2 process writes to the disk. This jbd2 process does not do anything if the disk is not plugged in. The noise also immediately stops if I unmont the drive, but keep it plugged in.
Total DISK READ: 0.00 B/s | Total DISK WRITE: 1838.15 K/s TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND 3727 be/3 root 0.00 B/s 0.00 B/s 0.00 % 0.15 % [jbd2/sdb1-8] 1 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % init 2 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kthreadd] 3 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/0] ...
First of all, the noise drives me crazy. I work in a quiet environment and this allbeit very low noise is so disturbing somehow.
Second, I think that these continuous writes to the disk might cause it's lifetime to degrade. This would be especially important for SSD drives, where the noise isn't present, but the same behavior can be observed. Moreover, I think that writes to the disk should not be necessary, since no user process is accessing the disk and the operating system surely does not need to access an external HDD for its operation.
What causes these write accesses and how to stop them?