My Linux Often crashes. What causes this problem?

I use the top command to view CPU usage
It is found that the idle usage is 0%, while iowait occupies 79%. This is a problem of the Redhat as 3 system, or caused by some processes. Please advise [from bbs.bitscn.com]

I searched for iowait usage on Google.
Very high % WIO, that is, the system I/O is busy, and the process obtains CPU but waits for I/O. The proportion of this part of time may be due to I/O problems ??......
If iowait is too high, it is generally the bottleneck of the disk, because both the IDE and SATA hard disks occupy the CPU while reading and writing ......
You can use the following command to find out the threads with high CPU usage:
Ps h-EO user, PID, ppid, tid, time, % CPU, CMD -- Sort = % CPU
First, specify the parameter 'H' to display thread-related information. The format output contains: User, PID, ppid, tid, time, % CPU, CMD, then, sort by the % CPU field. In this way, you can find the thread that occupies the processor. [From bbs.bitscn.com]

I know that I/O reading and writing is a problem. Our company's products use the Redhat as 3 operating system, and the file system ext3, which occupies a lot of CPU for reading and writing disks, in addition, our company's products are used to analyze and store logs. The problem may be that the file system is incorrectly selected.
Thank you for your confidence and reflection. [From bbs.bitscn.com]