Transcript presentation source

Clusters
Clusters
Alternative to symmetric multiprocessing
(SMP)
Group of interconnected, whole
computers working together as a unified
computing resource
illusion is one machine
system can run on its own
Clusters
Separate server
each computer is a separate server
no shared disks
need management or scheduling software
data must be constantly copied among
systems so each is current
Clusters
Standby Server with No Shared Disk
P
P
P
P
High-Speed Message Link
M
I/O
I/O
I/O
I/O
M
Clusters
Shared nothing
reduces communication overhead
servers connected to common disks
disks partitioned into volumes
each volume owned by a computer
if computer fails another computer gets
ownership of the volume
Clusters
Shared Disk
High-Speed Message Link
P
M
P
I/O
I/O
I/O I/O
I/O
RAID
P
P
I/O
M
Clusters
Shared disk
multiple computers share the same disks at
the same time
each computer has access to all of the
volumes on all of the disks
Win2000 Cluster Server
 Formerly called Wolfpack
 Shared-nothing cluster
 Concepts
Cluster Service – Software that manages cluster-specific activity
Resource – Item to be managed
Physical: Disk drives, Network cards
Logical: Volumes, TCP/IP addresses, Applications, Databases
Online – A resource is online at a node when it is providing
service on that node
Group – A collection of resources managed as a unit
Helps manage resources, load balancing
Usually a set of resources needed for a specific application
Win2000 Cluster Server
Components
Node Manager – Maintain membership: Uses heartbeat messages to track
system
Database Manager – Maintain cluster configuration database (resources,
groups, ownership): Uses fault-tolerant transaction software
Resource Manager – Make decisions concerning resources, startup, failover
Event Processor – Connect components
Beowulf
 From NASA High Performance Computing and Communications
Project, based on commodity hardware
 Implemented as an add-on to Linux, and each node runs a copy of
Linux, with kernel extensions for global namespaces
 Examples of Beowulf system software:
Beowulf Distributed Process Space – Allow process ID space to
span machines, provide single system image, start processes on
other nodes
Beowulf Ethernet Channel Bonding – Combine multiple low-cost
links into a single logical network
Pvmsync – Provide synchronization and shared data objects in a
cluster
EnFuzion – Set of tools for parametric computing