1. T. Kashiwagi, M. Suetake , K. Kourai (Kyushu Institute of Technology)
Migration of Virtual Machines Running across 　Multiple Hosts
T. Kashiwagi, M. Suetake , K. Kourai (Kyushu Institute of Technology)
Background
Host 1
Host 2
IaaS clouds provide virtual machines (VMs) with a large amount of memory
E.g., Amazon EC2 provides VMs with 4TB memory
Migrating large-memory VMs is difficult
VM migration needs sufficient free memory at the destination host VM VM
memory
memory
migrate
Issues
Split Migration [Suetake et al.’18]
Migrate one VM to multiple hosts
Main host : VM’s core and memory likely to be accessed
Sub-hosts : Rest of the memory
Run it as split-memory VM
Exchange memory data between multiple hosts with remote paging
Issue 1: Remote paging causes performance degradation
Up to 70% for in-memory DB
Issue 2: Maintenance of several hosts needs to stop the entire VM
　　　Main host VM
memory
Host 1
Main host
migrate VM VM
Memory
2TB
memory
1TB
memory
memory
1TB
　　Sub-host
Sub-host
Unified Migration
Partial Migration
Merge a VM across multiple hosts into one host again
Acceleration by parallel transfer of memory data
Improve memory access performance
No remote paging
Migrate only part of a split-memory VM
Main host only, sub-host only, etc.
Enable maintaining several hosts
Without stopping the VM
Main host 1
Main host 2
Main host
Host VM
migrate VM
memory
memory
メモリ
migrate
メモリ VM
memory VM
memory
remote paging
memory
memory
Sub-host
Sub-host
Experimental Results
migration time
throughput
Unified migration was 2x faster than traditional one
Thanks to parallel transfer
The performance of in-memory DB was improved by 11%
Compared with before unified migration