10.4 Frequent Hard Drive Activity

**PBK** · May 21st, 2010

Hello,

I have had Ubuntu 10.4 installed for the past three weeks and notice that the hard drive indicator light flashes about every second with no known activity. I am trying to figure out what is causing this as it's a replacement file server (Desktop install, though) at work and I am afraid of pre-mature hard drive failure on the WD 500Gb SATA Blue drives. I have unplugged the computer from the network to show me other computers are not accessing the server and iotop does not seem to accurately indicate what the hard drive activity is.

Maybe some help:

File system: EXT4.

Two WD 500Gb SATA Blue drives. No RAID setup - Separate, but both drives mounted.

Linux hbs 2.6.32-21-generic-pae #32-Ubuntu SMP Fri Apr 16 09:39:35 UTC 2010 i686 GNU/Linux.

4Gb RAM with 720 Mb RAM in use, 36Kb out of 12Gb Virtual RAM in use.

Running iotop -ao for one minute looks like this:

Code:

Total DISK READ: 0.00 B/s | Total DISK WRITE: 0.00 B/s
  PID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND                                            
  327 be/3 root          0.00 B    216.00 K  ?unavailable?  [jbd2/sda1-8]
  860 be/3 root          0.00 B    268.00 K  ?unavailable?  [jbd2/sda5-8]
  871 be/3 root          0.00 B     32.00 K  ?unavailable?  [jbd2/sdb5-8]
17777 be/4 postgres      0.00 B    224.00 K  ?unavailable?  postgres: stats collector process
  903 be/4 syslog        0.00 B     24.00 K  ?unavailable?  rsyslogd -c4
  963 be/4 proxy        20.00 K      0.00 B  ?unavailable?  (squid) -sY -f /etc/squid/squid.conf
  977 be/4 root          0.00 B      4.00 K  ?unavailable?  console-kit-daemon --no-daemon

I have stopped both PostgreSQL and Squid, but no change in LED activity. iotop updates every second, but I do not always see a change from iotop's screen every second. Maybe there is some caching going on..?

I am sure I am missing info above that may help, but is there any other way for me to see if this activity is necessary? Thanks any help!

Paul

**PBK** · May 24th, 2010

Anyone?

**Jeff Root** · June 8th, 2010

I came here to ask the same question, except that I have
Ubuntu 9.10 Karmic Koala.

The drive activity light flashes either once per second or
once overy two seconds. At the moment it is one per second.

I have disabled everything I could to make it stop, with no
effect. I turned off *everything* in the list of Startup
Applications. In BIOS I disabled the optical drive, the IDE
and Ethernet controllers, and SMART hard drive monitoring.
I unplugged the USB memory card reader. Flash, flash, flash.

ASUS P5Q-E motherboard
4 GB RAM
2 Western Digital 360 GB SATA hard drives
External dial-up modem connected to the 9-pin COM port

The System Monitor lists 144 processes. I do not know how
to interpret the information there. Less than half the
listed processes have values in the "Memory" column. The
rest say "N/A". I thought possibly that meant that those
processes were not loaded, but a small number of them did
appear to be running: A group of processes named "events"
and another named "kondemand".

I find it astonishing if 144 processes are loaded even with
all those startup options turned off. Among the processes
is Bluetooth, which doesn't exist on the computer.

-- Jeff, in Minneapolis

**cryptotheslow** · June 8th, 2010

I believe the jdb2/*** commands are to do with the ext4 filesystem journalling.

Try running

Code:

vmstat 1

in a Terminal whilst running iotop in another. You will see values appear in the bo (buffer out) column that coincide with the jbd2/*** commands appearing in iotop.

When idle with just iotop running I get 2 writes by the jbd2 command 3 seconds apart and then nothing for about 90 seconds - then the 2 writes again and so on. When actively using apps it is writing every few seconds.

(Lucid 32-bit with 2x WD Blue 320GB SATA drives)

It could be any number of things causing your more frequent writes e.g. a device driver writing to a log file somewhere.

Oh and Jeff - on Karmic you will probably see kjournald appearing at the top of iotop rather than jbd2/ commands.

**robert shearer** · June 24th, 2010

Yes, same here.
Excessive writes to disc.. every second..
can be seen on Gnome system monitor, can be heard from the disk, can be referenced to 'jbd2****' in iotop but cannot track down what causes it.

Anyone else with suggestions ??

possible similar behavior noted on Arch forum here...
http://bbs.archlinux.org/viewtopic.php?pid=692073