为提高效率，提问时请提供以下信息，问题描述清晰可优先响应。
- 【TiDB 版本】：1.0.5
- 【问题描述】：dm数据迁移因IO占满报错，无法启动且无法停止，报错信息如下：
code=30012:class=relay-unit:scope=upstream:level=high] start reader for UUID ed112399-616f-11e7-be97-18ded76e61ae.000001: start sync from position (mysql-bin.003441, 947789678): io.ReadFull(header) failed. err read tcp 10.194.2.47:36314-\u003e10.194.2.2:3306: i/o timeout: connection was bad\ngithub.com/pingcap/dm/pkg/terror.(*Error).Delegate\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/pkg/terror/terror.go:267\ngithub.com/pingcap/dm/pkg/binlog/reader.(*TCPReader).StartSyncByPos\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/pkg/binlog/reader/tcp.go:79\ngithub.com/pingcap/dm/relay/reader.(*reader).setUpReaderByPos\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/reader/reader.go:166\ngithub.com/pingcap/dm/relay/reader.(*reader).Start\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/reader/reader.go:111\ngithub.com/pingcap/dm/relay.(*Relay).setUpReader\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/relay.go:610\ngithub.com/pingcap/dm/relay.(*Relay).process\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/relay.go:304\ngithub.com/pingcap/dm/relay.(*Relay).Process\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/relay/relay.go:191\ngithub.com/pingcap/dm/dm/worker.(*realRelayHolder).run\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/relay.go:167\ngithub.com/pingcap/dm/dm/worker.(*realRelayHolder).Start.func1\ \t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/relay.go:143\ runtime.goexit\ \t/usr/local/go/src/runtime/asm_amd64.s:1357