This Different bandwidth optimization live VM migration schemes

This section
presents and compares VM migration op-timization schemes that consider
bandwidth, DVFS-enabled power, and storage optimization to reduce the side
effects of VM migration process. VM migration through LAN abuses network
attached storage (NAS) architecture to share the storage between communicating
servers. But, migrating a VM across WAN boundaries requires migrating large
sized storage in addition to VM memory over intermittent links


A. Bandwidth optimization


This section discusses effectively using of limited network capacity to
enhance application performance during the VM migration process. It also shows
a thematic taxonomy evaluation of existing schemes and comparisons between
bandwidth optimization schemes.


1)   Taxonomy
of bandwidth optimization schemes: Different bandwidth optimization live VM
migration schemes result in varying application downtime and total migration
time based on the nature of workload hosted within the migrant VM, type of
network link, number of con-current migrant VMs, and type of hypervisor
selected to manage server resources. The proposed scheme applies binary
XOR-based RLE (XBRLE) delta compression to improve VM migration performance.
Prior to triggering migration, a guest kernel conveys soft page addresses to
the VMM. For further improvement, the delta page is compressed using a light
weight compression algorithm.

2)   Review
of bandwidth optimization schemes: An opti-mized post-copy VM migration scheme
was proposed that exploits on-demand paging, active push, pre-paging, and
dynamic self-ballooning optimizations to pre-fetch memory pages at the receiver
host. Besides, growing bubbles around the pivot memory page to transfer
neighboring memory pages does not always improve VM migration performance,
especially when write-intensive applications are hosted within migrated VMs.
Active push transfers memory pages to the target server and ensures that every
page is sent exactly once from the source server. This scheme progresses by
transferring CPU registers and device states to the receiver host prior to VM
memory content migration.


3)   Comparison
of bandwidth optimization schemes: Many VM migration approaches have optimized
application down-time and total migration duration by employing optimization
and avoiding aggressive migration termi-nation a case of pre-copy. Moreover, an
optimization method presents additional overhead on shared resources like CPU,
memory, or cache

while optimizing VM
migration performance parameters such as downtime, total migra-tion time, and
application QoS. illustrates a qualitative comparison of VM migration schemes
based on selected parameters to highlight commonalities and variances in
existing bandwidth optimization schemes. Live VM migration schemes follow
either pre-copy post-copy, or hybrid migration patterns to migrate VMs across