Multiple instances of mysqld in iotop
Normal.
On some operating systems, MySQL shows up as a single process.  (There are probably &quot;threads&quot; inside it.)
On other operating systems, there is one main process, but each connection has its own process.  This is what you are seeing.
A combination of max_connections, &quot;connection pooling&quot;, thread_cache_size, user activity, and maybe some other things, lead to how many processes you will see.
Is it an issue?  Generally, no.  If you have configured things poorly, other clues will be more important than the number of processes in ps or top or iotop.  You are very likely to see that most of them are in &quot;Sleep&quot; mode when you do SHOW PROCESSLIST.  If you see lots of non-Sleep connections, the you may be missing some indexes (especially &quot;composite&quot; indexes) or have poorly formulated queries.  The slowlog is a better way to look for those.