Clustering Technology For Scaleability

1
Clustering TechnologyFor Scaleability

• Jim Gray
• Microsoft Research
• http//www.research.Microsoft.com/Gray

2
Cluster Shared What?

• Shared Memory Multiprocessor
• Multiple processors, one memory
• all devices are local
• DEC, SG, Sun Sequent 16..64 nodes
• easy to program, not commodity
• Shared Disk Cluster
• an array of nodes
• all shared common disks
• VAXcluster Oracle
• Shared Nothing Cluster
• each device local to a node
• ownership may change
• Tandem, SP2, Wolfpack

3
The AnswerBOTH SMP and Cluster?
Grow Up with SMP 4xP6 is now standard Grow Out
with Cluster Cluster has inexpensive parts
Cluster of PCs
4
Clusters being built

• Teradata 500 nodes (50k/slice)
• Tandem,VMScluster 150 nodes (100k/slice)
• Intel, 9,000 nodes _at_ 55M ( 6k/slice)
• IBM 512 nodes _at_ 100m (200k/slice)
• PC clusters (bare handed) at dozens of nodes web
  servers (msn, PointCast,), DB servers
• KEY TECHNOLOGY HERE IS THE APPS.
• Apps distribute data
• Apps distribute execution

5
So, Whats New?

• When slices cost 50k, you buy 10 or 20.
• When slices cost 5k you buy 100 or 200.
• Manageability, programmability, usability become
  key issues (total cost of ownership).
• PCs are MUCH easier to use and program

6
So, Whats New?

• PCs create virtuous cycle

Vicious Cycle No Customers!
Virtuous Cycle Standards allow progress and
investment protection
Apps
Standard OS Hardware
Customers
7
What is Wolfpack?

• A consortium of 60 HW SW vendors(everybody who
  is anybody)
• A set of APIs for clustering and fault tolerance
• An enhancement to NT Server (in beta test )
• Key concepts
• System a particular node
• Cluster a collection of systems working together
  
• resource a hardware or software module
• resource dependency one resource needs another
• resource group fails over as a unit
  dependencies do not cross group boundaries

8
What is Wolfpack?
Cluster Management Tools
Cluster Api DLL
RPC
Cluster Service
Global Update
Database
Manager
Manager
Node
Event Processor
Manager

Mgr
Failover
Communication
App
Manager
Resource
Mgr
Resource
Other Nodes
DLL
Open Online IsAlive LooksAlive Offline Close
Resource
Resource Monitors
Management
Interface
Physical
Logical
App
Resource
Resource
Resource
DLL
DLL
DLL
Cluster Aware
App
9
Cluster Advantages

• Clients and Servers made from the same stuff.
• Inexpensive Built with commodity components
• Fault tolerance
• Spare modules mask failures
• Modular growth
• grow by adding small modules
• Parallel data search
• use multiple processors and disks

10
Single System ImageIs It Important?

• Yes, if you dont have it you fail
• parallel MPPs vs Tandem, Teradata, VAXcluster.
• NUMA Cluster
• some things are farther away.
• Must program in parallel to
• utilize multiple cpus, disks, wires
• OS, DBMS, TPmonitor, Web Server, ORB give
  transparency load balance data and programs.
• Administrator, Programmer, User
• do not want to know about program data location

11
What Happens When a Component Fails?

• Redundant disk or path configure around it.
• Non-redundant software restart.
• Non-redundant hardware migrate software to
  surviving nodes.
• Fault detection 1 ms to 10 sec.
• Failover .1 sec to 1 min.
• This is standard in Tandem, Teradata, VMScluster

12
What are Support Costs?

• Cluster lowers support costs by
• masking failures (instant repair via spare
  modules)
• allowing online maintenance and upgrades.
• Commodity parts are much cheaper
• 10/MIPS vs 10,000/MIPS
• 1k/OS vs 30K/month/OS
• Moden OSs are easier to install, configure,
  manage
• GUI
• Self-tuning
• Online and task-based help
• Built in wizards