| 63 | 63 | Figure 3 shows the downtime results under highnet and highsys. We observe that under highsys, [wiki:LLM LLM] incurs a downtime that is longer than, yet comparable to, that of [http://nss.cs.ubc.ca/remus/ Remus]. The reason is that, [wiki:LLM LLM] runs at low frequency, hence the migration traffic in each period is higher than that of [http://nss.cs.ubc.ca/remus/ Remus]. Under highnet, the downtime of [wiki:LLM LLM] and [http://nss.cs.ubc.ca/remus/ Remus] show a reverse relationship, where [wiki:LLM LLM] outperforms [http://nss.cs.ubc.ca/remus/ Remus]. This is because, from the client side, there are too many duplicated packets to be served again by the backup machine in [http://nss.cs.ubc.ca/remus/ Remus]. In [wiki:LLM LLM], on the contrary, the primary machine migrates the requested packets as well as boundaries to the backup machine, i.e., only those packets yet to be served are served by the backup. Thus the client does not need to re-transmit the requests, and therefore experiences a shorter downtime. |
