Hight disk latency after changing kernel

May 22, 2014 2.3k views
TonyTsang
By:
TonyTsang
After changing kernel (upgrading from ubuntu 12.04 to 13.04) Munin start warning me the disk performance, like the following image. The avg io wait r/w stay at around 30 seconds. http://picpaste.com/disk_latency-TuJXeSQS.png But strangely enough, the server is running fine and no disk performance issue encountered. When I verify it with the following command, the result seems normal. sudo ioping /dev/vda -c 30 --- /dev/vda (device 30.0 GiB) ioping statistics --- 30 requests completed in 29.0 s, 911 iops, 3.6 MiB/s min/avg/max/mdev = 363 us / 1.1 ms / 3.4 ms / 668 us Does munin reading something wrong, or did I miss something?
3 Answers
Kernel infos:
Original kernel: vmlinuz-3.8.0-38-generic (12.04)
Current kernel: vmlinuz-3.13.0-24-generic (14.04)
Its seems to be a kernel bug. Have the same problem when I went from 13.10 to 14.04 see https://www.digitalocean.com/community/questions/14-04-munin-disk-latency

Thanks for the info.

I can safely ignore the warning now.
Have another answer? Share your knowledge.