Shulou(Shulou.com)06/02 Report--

Accident background: KVM virtualization is installed on the physical machine (192.168.200.10). The virtualized machine cannot be started normally. Enter the vnc interface to check that the Linux system takes about 30s-60s to read the hard disk. If it starts normally, it will take a few seconds. Suspect it has something to do with the hard drive. Solution:

1. Check the current system hard disk load

See which processes are consuming hard disk IO

Step 1: Use iostat -x 1 iostat There is also a common option-x, which will be used to display extended data related to io. rrqm/s: How many read requests related to this device are merged per second (when the system call needs to read data, VFS sends the request to each FS, if FS finds that different read requests read data from the same Block, FS will merge this request);wrqm/s: How many write requests related to this device are merged per second. rsec/s: sectors read per second;wsec/: sectors written per second. rKB/s： The number of read requests that were issued to the device per second;wKB/s: The number of write requests that were issued to the device per second;avgrq-sz avgqu-sz is the average request queue length. There is no doubt that the shorter the queue length, the better. await: Average processing time per IO request (in microseconds). Here can be understood as IO response time, generally system IO response time should be less than 5ms, if more than 10ms is relatively large. This time includes queue time and service time, that is, in general, await is greater than svctm, the smaller the difference, the shorter the queue time, and the larger the difference, the longer the queue time, indicating that the system has a problem. svctm Represents the average service time per device I/O operation in milliseconds. If svctm is close to await, there is little I/O waiting and disk performance is good, and if await is much higher than svctm, the I/O queue is waiting too long, Applications running on the system will slow down. % util: All processing IO time within the count time, divided by the total count time. For example, if the count interval is 1 second and the device has 0.8 seconds to process IO and 0.2 seconds to idle, then %util = 0.8/1 = 80% for the device, so this parameter implies how busy the device is. In general, if this parameter is 100% it means the device is running close to full capacity (of course if it is multi-disk, even if %util is 100%, disk usage may not reach a bottleneck because of disk concurrency).

The conclusion is that the load of hard disk has reached the bottleneck;

Step 2: Use iotop, similar to top. See which process is consuming hard disk IO, as shown in the figure:

Conclude that one VM (192.168.200.207) is consuming hard disk IO, which is resolved after shutdown

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.