Mysql – Clusters

© April 13, 2023 Novell Inc, Confidential & Proprietary2

Sleeping Pills

1. Clustering – What is it?

2. Mysql Clustering – Native Support.

3. EMIC Enterprise Application Cluster for Mysql.

4. Leveraging Novell Clustering Services for Mysql.

5. Cluster JDBC.

6. Oracle RAC.

7. Mysql Native Clustering support future.

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1. About Clustering

1. Clustering : What is it?a. Shared Disk Approach.

b. Shared Nothing Approach.

c. Federated Databases.

2. Need for it :a. Load Balancing.

b. Fault tolerance.

c. Scalability.

d. Sometimes Online Backup tooo.

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About Clustering (contd..)

3. Important Features of clustering :

a. IP Sharing.

b. Seemless Connections on Fail over.

c. Complete Abstraction to applications on Clustering functions.

d. Centralized Management of cluster nodes.

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2. Mysql Clustering – Native Support.

Mysql Natively has these two options for clustering.

1. Shared Nothing Approach : Replication.

2. Shared Data Directory.

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Mysql-Replication

How do they work?

Master

Slave1

Slave 2

Clients D

oing Selects

Clients Doing Updates

Insert & Update

Insert & Update

Selects

Select

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Mysql-Replication (contd.)

Source – BS2003 presentation TUT205

How are they Useful?1. Load Balancing.

2. Fault tolerance.

3. Scalability.

4. Online Backup

S1

S2

S3

M1Client1

Client2

Client1

Client2

S3

S1

S2

M1

When M1 goes Down

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Mysql Replication (Contd.)

3. Issues and some obvious reasons !!!.1. Slaves Always lag behind the Master.

2. Virtual IPAddress??

3. Scalability is Limited to Number of selects??

4. No Abstraction provided to Client.

Solution :-

Use Spread or Message passing for synchronous replication

Two Phase commit approach.

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Mysql – Shared Data Directory.

How to set up?

2. How are they Useful ?• Provides all the functionalities of replication.

• Master and slaves will be always in sync.

Server1 Server2

Shared Data dir

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Shared Data directory (contd.)

3. Issues & Some obvious reasons.

a. Locking issues with Innodb.

b. query caches might result in false data.

c. Very slow over Network File System or Remote File system that can be shared across two machines.

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1. What is it?a. Provides Application Level clustering.

b. Uses shared Nothing Approach.

c. Comprehensive clustering solution for Mysql.

3. EMIC EAC for Mysql

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EMIC EAC For Mysql (Contd..)

2. Software Architecture.

EMIC EAC Software Architecture

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EMIC EAC For Mysql (Contd..)

3. How it works.

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EMIC EAC for Mysql ( Contd…)

4. What are the clustering features do they address?

– Dynamic Load Balancing.

– Seemless connections.

– Virtual IP.

– Scalability.

– Complete transparency and Centralized Mangement.

Cons :– Might be slower than because of additional complex

clustering logic provided by EMIC ( Not tested Hence No data.. I have started testing it If data proves assumption wrong then I will remove this )

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4. Leveraging NCS for Mysql on Netware

What is NCS?1. Clustering framework for all services running on

NetWare 6 and above.

2. Shared disk approach through SAN (Fibre channel) or ISCSI.

Server1 Server2 Server3 Server1 Server2 Server3

Fibre Channel Switch

Shared Disk System

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NCS for Mysql on Netware (Contd..)

Clustering Features Addressed!!!1. Fault tolerance.2. Virtual IP Address.3. Seemless connections.4. Complete Abstraction and Centralized

management through e-directory.

Features that can be Added.- Application level load balancing is not yet

supported for Mysql through NCS. NCS provides load balancing by moving the applications across different Machines. Load balancing by running the same applications in two Cluster nodes is not yet provided.

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5. Cluster JDBC

What is it?1. Database cluster middleware through jdbc

driver.

2. Provides clustering support only for Java Applications.

3. It provides complete abstraction to java applications accessing cluster databases.

4. Provides clustering support across Multiple database types.

5. Open source software under LGPL.

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Cluster JDBC (Contd…)

Software Architecture

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Cluster JDBC (Contd…)

Pros – Scalability.– Load Balancing.– Fault tolerance.– Client Side abstraction (Very minimal

changes to the Java applications).– Seemless connections.

Cons– Slow because of one layer of additional

processing. – Only Java applications can leverage them.

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6. Oracle RAC

How is clustering done?– Shared Disk Approach.

– Cache Fusion Architecture.

Architecture.Cluster Interconnect

Shared storage Subsystem

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Pros– Scalability.

– Load Balancing through Funtion shipping and Data Shipping.

– High Availability (handles N-1 Node failures)

– Seemless connections.

– Data access during recovery.

Cons– VirtualIP Address is not supported.

Oracle RAC

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7. Mysql clustering Native Support-Future

NDB

• What is it? : It’s the cluster technology that Mysql has got through the Acquisition of Alzato.

• What might be native clustering support in Mysql in Future through NDB?

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