使用mgo的mongodb错误：net.OpError（net.timeoutError）

I keep getting errors when writing to mongo at unpredictable times and would like to find out the reason. I am using the mgo driver for Go. The error is of type net.OpError. Some of its relevant fields:

net.OpError{
  Err: net.timeoutError,
  Op: "read",
  Net: "tcp",
}

Currently I handle this error by reconnecting:

err := myType.mgoCollection.Insert(msg)
if err != nil {
    myType.mgoSession = myType.mgoSession.Copy()
    myType.mgoCollection = myType.mgoSession.DB("my_db_name").C("my_collection_name")
}

and re-submit. Sometimes this is enough, sometimes several retries are needed. And sometimes even after 10 retries (each around 1 minute) the error is still there (currently I break up after 10 retries).

I could not find anything suspicious in the mongodb logs and do not know where to look further.

Most of my writes to mongo are rather small, but twice a second there are somewhat larger writes (maybe 1 or 10 kb when represented as JSON string).

I have two separate processes and this error occurs for both of them at the same time.