On Friday 25 April 2014 05:48 PM, Mulyadi Santosa wrote:
Could it be a power management system trying to spin down your disk to save power?
Try to alter the power management variable from your desktop environment settings. Try to make it less aggresive.
Tried setting APM to 254, so as not to attempt a spin down, but no change in the situation. But even if its the system trying to spin down, would it get listed as a write operation? Isnt it supposed to be an ioctl ? Does iotop consider ioctls as a write ? Its man page doesnt mention anything about ioctls.
ALso, it could be the I/O scheduler too. Try to switch to noop and see if it change the situation
Under noop, deadline and cfq, the situation remains the same. Dont have any other schedulers. The kworker I mentioned was spotted from the output of iotop -o. I kept "watching" /proc/meminfo while kworker was popping up. I found that even though the same kworker showed up periodically at 1 second, meminfo's "dirty" entry was getting modified only at about 45 seconds, with 8KB, and subsequently after 1 minute, dirty would roll back to zero, (probably indicating a real disk write?). Iotop says it reports acutal I/O happening, and this seems consistent with the above observation. But in reality, my HDD indicator is blinking at 1 second, synchronous to kworker. Does the hdd indicator blink under any circumstances other than a read or write? BTW its a light blink, not a strong one like when we do some serious I/O. Can you please do an "iotop -o" and see if you also have the same kworker popping up? Thanks and Regards, Jay