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Mecanismos de alta disponibilidad
con Microsoft SQL Server 2008
Por: ISC Lenin López Fernández de Lara
Temario
Database Mirroring
Log Shipping
Replication
Failover Clustering
Demo
1.1 Database Mirroring Roles
1.2 Operating Modes
High Availability
High SafetyHigh
Performance
1.2.1 High Availability Operating
Mode
synchronous
Automatic failover
Writes a
transaction to
th transaction
log
The
transaction is
first committed
on the mirror
database
Performance
impact
Uses simple ping
1.2.2 High Performance Operating Mode
Asynchronou
s
No automatic
failover
1.2.3 High Safety Operating
Mode
Synchronous
Manually failover
Writes a
transaction to
th transaction
log
The
transaction is
first committed
on the mirror
database
Performance
impact
Log Shipping
¿What is?
Provides a means to maintain a secondary server
on an automated basis using a chain of transaction
log backups
Also allows you to configure a monitor server that
can verify the health
1.1 Log Shipping Scenarios
OffloadingReportActivity
Initializationfor
DatabaseMirroring
Upgrading Versions or Migrating to
a New Platform
Primary or Secondary Availability Solution
1.1.1 Offloading Report
Activity
Reportingserver
SELECT statements
StandbyMode
1.1.2 Initialization for Database Mirroring
backups of theprincipal
principal and mirror are
synchronized
minimizesthe time
1.1.3 Upgrading Versions or
Migrating to a New Platform
build the new instance
a brief outage on
the applications
move thedatabases
1.1.4 Primary or Secondary
Availability Solution
Secondarydatabases
an outage of the
primary database
thatapplicationscan switch
1.2 Log Shipping Components
Replication
¿What is?
Replication is designed as a data-distribution
mechanism.
The core replication engine is designed for very
flexible implementation
The core architecture can be used to provide
availability for a database because a redundant
copy of data is maintained in synchronization with
a master copy
1.1 Replication Components
• The basic building block of replication
• Can be defined against a table, view, stored procedure, or function
Articles
• Publications are groupings of articles that define the replication setPublications
• You can apply one or more filters to each article that restrict the set of data that is replicated.
• You can fi lter articles by rows or by columns
Filters
1.2 Replication Roles
• Maintains the master copy of the data within a replication architecturepublisher
• Is the database that is receiving changes from the replication engine defined by the publication to which it is subscribing
subscriber
• Is the main engine within a replication architecture
• The distribution database is stored on the instance that is configured as the distributor (An instance of SQL).
distributor
1.3 Replication Topologies
Central Publisher
OtherCentral
Subscriber
1.3.1 Central Publisher
Topology
1.3.2 Central Subscriber
Topology
1.6 Replication Methods
SnapshotReplication
MergeReplication
TransactionalReplication
1.6.1 Snapshot Replication
1. Snapshot Agent
extracts the
schema and BCPs
the data
2. Distribution Agent then
picks up and applies the
snapshot to each
subscriber (tables are
dropped and re-created,
then the data is copied
using BCP)
It is not
normally
used for high
availability
full replace of
data
1.6.2 Transactional
Replication
Begins with an initial snapshot being applied to the
subscriber to ensure that the two databases are
synchronized
As subsequent transactions are issued against the
publisher, the replication engine applies them to the
subscriber.
2.2 Transactional Options
Merge Replication
¿What is?
Merge replication is another alternative that can be
applied to high-availability systems.
Merge replication was primarily designed for mobile,
disconnected users.
By translation, the mechanisms are already built in
for changes to occur at any location and get
synchronized, as well as to be able to withstand
failures and continue processing
3.1 Change Tracking
(synchronize process)
MSmerge
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ory
MSmerge
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e
MSmerge
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ory
MSmerge
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e
Windows Clustering
¿What is?
Windows clustering enables multiple pieces of
hardware to act as a single platform for running
applications.
1.1 Windows Cluster
Components
1.2 Types of Clusters
Standard Windows Cluster
MajorityNodeSet
Cluster
2.2 Failover Cluster Instance Components
The components that you need to configure for a SQL
Server failover clustered instance are the following:
IP addresses
Network names
Disk drives on the shared drive array
SQL Server services
Service accounts
Demo
Mirroring High Availability
¿######?