This document provides an overview of SQL Server architecture and components. It discusses common SQL Server versions, the different components that make up SQL Server like databases, files, transaction logs, and recovery models. It also covers new features introduced in SQL Server 2005 and 2012 like data partitioning using file groups, database snapshots, database mirroring, and availability groups.

1. Tom Hamilton – America’s
Channel Database CSE
Microsoft
SQL Server
Architecture

2. Common SQL Server Versions
 SQL Server 2000
 SQL Server 2005
– Product Overview
 SQL Server 2008
– Product Overview
 SQL Server 2012
– Product Overview

3. SQL Server Components
 Databases
 Database Files and File Groups
 Transaction Logs
 Backup and Recovery
 Microsoft Clusters
 Protocols
 Disaster Recovery

4. SQL Server Databases
 System databases
– Master
– Model
– MSDB
– Resource
– Tempdb
 User databases

5. SQL Server Files
 Binaries
 Datafiles (.mdf, .ndf)
 Transaction log files (.ldf)
 Backup files and snapshot files
 File groups

6. SQL Server 2005 New Feature: Data Partitioning Using
File Groups
Resources:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnsql90/html/sql2k5partition.asp
http://www.microsoft.com/sql/bi/ProjectREAL/default.mspx
http://msdn.microsoft.com/en-us/library/ms190787

7. SQL Server Transaction Log
When the end of the logical log reaches the end of the physical log file,
the new log records wrap around to the start of the physical log file.

8. SQL Server Recovery Model
Architectures
 Three Models:
– Simple: Truncate occurs on checkpoint (default in SQL2000)
 No “roll-forward” capability
 Data loss acceptable
– Bulk Logged: All operations are logged except bulk operations (BCP,
BULK, etc) (DSS environments)
 Roll forward capability
 Some data loss acceptable
– Full: All ops are logged (Default for SQL Server 2005)
 Full roll forward/back
 Least amount of data loss possible

9. SQL Server Recovery Model
Architectures
Recovery
Model
Description Work Loss Exposure Recover to point
in time?
Simple No log
backups
Changes since the most
recent backup are
unprotected
Can recover only
to the end of a
backup
Full Requires log
backups
Normally none Can recover to a
specific point in
time
Bulk
logged
Requires log
backups
If the log is damaged or
bulk-logged operations
occurred since the most
recent log backup,
changes since the last
backup must be redone
Point in time is not
supported

10. SQL Server 2005 New Feature: DB Snapshots – Copy
on write
Key Points from SQL Books Online (BOL)
Intended for reporting to a point in time at mirror
site or locally
Performance is reduced due to increased I/O on
the source database resulting from a copy-on-
write operation to the snapshot every time a
page is updated.
Snapshots of the model, master, and temp
databases are prohibited.
Specifications of the database snapshot files
cannot be changed.
Files cannot be dropped from a snapshot.
Can’t backup or restore snapshots.
Can’t attach or detach snapshots.
Can’t clone a snapshot.

11. Microsoft Cluster Server
 Implementation Considerations
 Hardware
 Software
 Network

12. Protocols
 FCP
 iSCSI
 SCSI/NFS?
 SMB

13. SQL Server 2005 New Feature: DB Mirroring
 Database Failover
– Very fast failover – less than 3
seconds
– Automatic or manual failover
 Works with dissimilar hardware and
storage
 Sync and async modes supported
 More info:
http://www.microsoft.com/technet/pro
dtechnol/sql/2005/dbmirror.mspx

14. Microsoft SQL Server Mirror Vs.
SnapMirror

15. Microsoft SQL Server Mirror Vs.
SnapMirror
Data transfers
Licenses
Server-server vs. controller-controller
Reversible sync
Failover
Database only vs. everything
Go for win-win

16. New in SQL Server 2012
 Availability Groups
– http://msdn.microsoft.com/en-us/library/cc645581.aspx
 SMB
– http://msdn.microsoft.com/en-us/library/hh759341.asp

17. SQL Server Replication
 Transactional Replication
 Merge Replication
 Snapshot replication